criyle/codenet-compile-errors huggingface dataset:
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  cin >> S;

  cout << 'AtCoder ' << s.at(9) << ' Contest' <<endl;
}


Compiler output:
a.cc:8:11: warning: multi-character literal with 8 characters exceeds 'int' size of 4 bytes
    8 |   cout << 'AtCoder ' << s.at(9) << ' Contest' <<endl;
      |           ^~~~~~~~~~
a.cc:8:36: warning: multi-character literal with 8 characters exceeds 'int' size of 4 bytes
    8 |   cout << 'AtCoder ' << s.at(9) << ' Contest' <<endl;
      |                                    ^~~~~~~~~~
a.cc: In function 'int main()':
a.cc:8:25: error: 's' was not declared in this scope
    8 |   cout << 'AtCoder ' << s.at(9) << ' Contest' <<endl;
      |                         ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  string s;
  
  cout <<'A' << stirng.at(0) << C << endl;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:7:17: error: 'stirng' was not declared in this scope
    7 |   cout <<'A' << stirng.at(0) << C << endl;
      |                 ^~~~~~
a.cc:7:33: error: 'C' was not declared in this scope
    7 |   cout <<'A' << stirng.at(0) << C << endl;
      |                                 ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  string s;
  
  cout <<'A' << stirng.at(1) << C << endl;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:7:17: error: 'stirng' was not declared in this scope
    7 |   cout <<'A' << stirng.at(1) << C << endl;
      |                 ^~~~~~
a.cc:7:33: error: 'C' was not declared in this scope
    7 |   cout <<'A' << stirng.at(1) << C << endl;
      |                                 ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string a,b,c;
  cin >>a >>b >>c;
  cout <<A <<b.at(0) <<C <<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:10: error: 'A' was not declared in this scope
    7 |   cout <<A <<b.at(0) <<C <<endl;
      |          ^
a.cc:7:24: error: 'C' was not declared in this scope
    7 |   cout <<A <<b.at(0) <<C <<endl;
      |                        ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
 string a,b,c,B;
 cin a >> b >> c;
 
 B = b[0];
  
 cout << 'A' + B + 'C' << endl;
  
  
}


Compiler output:
a.cc: In function 'int main()':
a.cc:6:5: error: expected ';' before 'a'
    6 |  cin a >> b >> c;
      |     ^~
      |     ;
Language: C++

#include<iostream>
using namespace std;
int main(){
  string s,s2;
  cin >> s2 >> s >> s2;
  cout << "A"+s[0]+"C" <<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:19: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    6 |   cout << "A"+s[0]+"C" <<endl;
      |                   ^~~~
      |                    |
      |                    const char [2]
Language: C++

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
  string a,b,c,s; cin >> a >> b >> c;
  s = a.at(0) + b.at(0) + c.at(0);
  transform(s.begin(), s.end(), s.begin(), std::toupper);
  cout << s << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:12: error: no matching function for call to 'transform(std::__cxx11::basic_string<char>::iterator, std::__cxx11::basic_string<char>::iterator, std::__cxx11::basic_string<char>::iterator, <unresolved overloaded function type>)'
    9 |   transform(s.begin(), s.end(), s.begin(), std::toupper);
      |   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:4:
/usr/include/c++/14/bits/stl_algo.h:4209:5: note: candidate: 'template<class _IIter, class _OIter, class _UnaryOperation> _OIter std::transform(_IIter, _IIter, _OIter, _UnaryOperation)'
 4209 |     transform(_InputIterator __first, _InputIterator __last,
      |     ^~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4209:5: note:   template argument deduction/substitution failed:
a.cc:9:12: note:   couldn't deduce template parameter '_UnaryOperation'
    9 |   transform(s.begin(), s.end(), s.begin(), std::toupper);
      |   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4247:5: note: candidate: 'template<class _IIter1, class _IIter2, class _OIter, class _BinaryOperation> _OIter std::transform(_IIter1, _IIter1, _IIter2, _OIter, _BinaryOperation)'
 4247 |     transform(_InputIterator1 __first1, _InputIterator1 __last1,
      |     ^~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4247:5: note:   candidate expects 5 arguments, 4 provided
In file included from /usr/include/c++/14/algorithm:86:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:156:1: note: candidate: 'template<class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2> std::transform(_ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _UnaryOperation)'
  156 | transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
      | ^~~~~~~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:156:1: note:   candidate expects 5 arguments, 4 provided
/usr/include/c++/14/pstl/glue_algorithm_defs.h:162:1: note: candidate: 'template<class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator, class _BinaryOperation> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2> std::transform(_ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator, _BinaryOperation)'
  162 | transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
      | ^~~~~~~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:162:1: note:   candidate expects 6 arguments, 4 provided
Language: C++

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main(){
  string a,b,c,s; cin >> a >> b >> c;
  s = a.at(0) + b.at(0) + c.at(0);
  transform(s.begin(), s.end(), s.begin(), std::toupper);
  cout << s << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:12: error: no matching function for call to 'transform(std::__cxx11::basic_string<char>::iterator, std::__cxx11::basic_string<char>::iterator, std::__cxx11::basic_string<char>::iterator, <unresolved overloaded function type>)'
    8 |   transform(s.begin(), s.end(), s.begin(), std::toupper);
      |   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:61,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_algo.h:4209:5: note: candidate: 'template<class _IIter, class _OIter, class _UnaryOperation> _OIter std::transform(_IIter, _IIter, _OIter, _UnaryOperation)'
 4209 |     transform(_InputIterator __first, _InputIterator __last,
      |     ^~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4209:5: note:   template argument deduction/substitution failed:
a.cc:8:12: note:   couldn't deduce template parameter '_UnaryOperation'
    8 |   transform(s.begin(), s.end(), s.begin(), std::toupper);
      |   ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4247:5: note: candidate: 'template<class _IIter1, class _IIter2, class _OIter, class _BinaryOperation> _OIter std::transform(_IIter1, _IIter1, _IIter2, _OIter, _BinaryOperation)'
 4247 |     transform(_InputIterator1 __first1, _InputIterator1 __last1,
      |     ^~~~~~~~~
/usr/include/c++/14/bits/stl_algo.h:4247:5: note:   candidate expects 5 arguments, 4 provided
In file included from /usr/include/c++/14/algorithm:86:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:156:1: note: candidate: 'template<class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2> std::transform(_ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _UnaryOperation)'
  156 | transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
      | ^~~~~~~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:156:1: note:   candidate expects 5 arguments, 4 provided
/usr/include/c++/14/pstl/glue_algorithm_defs.h:162:1: note: candidate: 'template<class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator, class _BinaryOperation> __pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2> std::transform(_ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator, _BinaryOperation)'
  162 | transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
      | ^~~~~~~~~
/usr/include/c++/14/pstl/glue_algorithm_defs.h:162:1: note:   candidate expects 6 arguments, 4 provided
Language: C++

#include <iostream>
#include <string>
using namespace std;
int main(){
  string a,b,c,s; cin >> a >> b >> c;
  s = a.at(0) + b.at(0) + c.at(0);
  transform(s.begin(), s.end(), s.begin(), std::toupper);
  cout << s << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:3: error: 'transform' was not declared in this scope
    7 |   transform(s.begin(), s.end(), s.begin(), std::toupper);
      |   ^~~~~~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  cin >> S;

  cout << "A" + S.at(8) + "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:25: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    8 |   cout << "A" + S.at(8) + "C" << endl;
      |           ~~~~~~~~~~~~~ ^ ~~~
      |               |           |
      |               const char* const char [2]
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main() {
  string s; cin >> s;
  char c = s.at(0);
  cout << "A" + c + "C" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:19: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    7 |   cout << "A" + c + "C" << endl;
      |           ~~~~~~~ ^ ~~~
      |               |     |
      |               |     const char [2]
      |               const char*
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string A;
  string X;
  string C;
    cin>>A>>X>>C;
  
  cout<<A.at(0)X.at(0)C.at(0)<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:16: error: expected ';' before 'X'
   10 |   cout<<A.at(0)X.at(0)C.at(0)<<endl;
      |                ^
      |                ;
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string tmp, s;
  cin >> tmp >> s;
  s = "A"+s.at(0)+"C";
  cout << s << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:18: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    7 |   s = "A"+s.at(0)+"C";
      |       ~~~~~~~~~~~^~~~
      |          |        |
      |          |        const char [2]
      |          const char*
Language: C++

#include <iostream>
#include <string>
using namespace std;

int main() {
  string s1, s2, s3;
  cin >> s1 >> s2 >> s3;
  cout << s[0] << s[1] << s[2] << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:11: error: 's' was not declared in this scope; did you mean 's3'?
    8 |   cout << s[0] << s[1] << s[2] << endl;
      |           ^
      |           s3
Language: C++

#include<iostream>
#include<string>
#include <algorithm>
using namespace std;
int main()
{
  string s;
  cin >> s;

  int position = s.find(' ')
  cout << "A" << s[position+1] << "C" << endl;

  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:3: error: expected ',' or ';' before 'cout'
   11 |   cout << "A" << s[position+1] << "C" << endl;
      |   ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  cin >> s;
  char s = S.at(9);
  cout << "A" << s << "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:6:10: error: 's' was not declared in this scope
    6 |   cin >> s;
      |          ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  char s;
  cin >> s;
  s = S.at(9);
  cout << "A" + s + "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:19: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    9 |   cout << "A" + s + "C" << endl;
      |           ~~~~~~~ ^ ~~~
      |               |     |
      |               |     const char [2]
      |               const char*
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string S;
  char s;
  cin >> s;
  s = S.at(9);
  cout << A << s << C << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:11: error: 'A' was not declared in this scope
    9 |   cout << A << s << C << endl;
      |           ^
a.cc:9:21: error: 'C' was not declared in this scope
    9 |   cout << A << s << C << endl;
      |                     ^
Language: C

#include<stdio.h>

int main(){
  char s[100];
  scanf("AtCoder %s Contest", s);
println("A%cC", s[0]);
  return 0;
}



Compiler output:
main.c: In function 'main':
main.c:6:1: error: implicit declaration of function 'println'; did you mean 'printf'? [-Wimplicit-function-declaration]
    6 | println("A%cC", s[0]);
      | ^~~~~~~
      | printf
Language: C

#include<stdio.h>

int main(){
  char s[100],;
  scanf("AtCoder %s Contest", s);
println("A%cC", s[0]);
  return 0;
}



Compiler output:
main.c: In function 'main':
main.c:4:15: error: expected identifier or '(' before ';' token
    4 |   char s[100],;
      |               ^
main.c:6:1: error: implicit declaration of function 'println'; did you mean 'printf'? [-Wimplicit-function-declaration]
    6 | println("A%cC", s[0]);
      | ^~~~~~~
      | printf
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
	string title;
	cin >> title ;
	char  dai[sizeof(title)] = title;

	cout << "A" << dai.at(8) << "C" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:36: error: array must be initialized with a brace-enclosed initializer
    7 |         char  dai[sizeof(title)] = title;
      |                                    ^~~~~
a.cc:9:28: error: request for member 'at' in 'dai', which is of non-class type 'char [32]'
    9 |         cout << "A" << dai.at(8) << "C" << endl;
      |                            ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
	string title;
	cin >> title ;
	char  dai[sizeof(title)) = title;

	cout << "A" << dai.at(8) << "C" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:32: error: expected ']' before ')' token
    7 |         char  dai[sizeof(title)) = title;
      |                                ^
      |                                ]
a.cc:9:24: error: 'dai' was not declared in this scope
    9 |         cout << "A" << dai.at(8) << "C" << endl;
      |                        ^~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
	string a,b,c;
	cin>>a>>b>>c;
	cout<<A<<b.at(0)<<C<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:15: error: 'A' was not declared in this scope
    7 |         cout<<A<<b.at(0)<<C<<endl;
      |               ^
a.cc:7:27: error: 'C' was not declared in this scope
    7 |         cout<<A<<b.at(0)<<C<<endl;
      |                           ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string s;
  cin>>s;
  cout<<A<<s.at(8)<<C<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'A' was not declared in this scope
    7 |   cout<<A<<s.at(8)<<C<<endl;
      |         ^
a.cc:7:21: error: 'C' was not declared in this scope
    7 |   cout<<A<<s.at(8)<<C<<endl;
      |                     ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string A, s, C;
  cin >> A >> s >> C;
  cout << "A" + s.at(0) + "C";
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:25: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    7 |   cout << "A" + s.at(0) + "C";
      |           ~~~~~~~~~~~~~ ^ ~~~
      |               |           |
      |               const char* const char [2]
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string S;
  cin >> S;
  cout << "A" + S[8] + "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:22: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    7 |   cout << "A" + S[8] + "C" << endl;
      |                      ^ ~~~
      |                        |
      |                        const char [2]
Language: C++

#include<bits/stdc++.h>

using namespace std;
int main(){
  string x, y, z;
  cin >> x >> y >> z;
  cout << A << y.at(0) << C << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:11: error: 'A' was not declared in this scope
    7 |   cout << A << y.at(0) << C << endl;
      |           ^
a.cc:7:27: error: 'C' was not declared in this scope
    7 |   cout << A << y.at(0) << C << endl;
      |                           ^
Language: C++

using namespace std;
#include<bits/stdc++.h>
#define BEGIN ios_base::sync_with_stdio(0);cin.tie(0);
#define END return EXIT_SUCCESS;
#define FOR(I,A,B) for((I)=(A);(I)<(B);(I)++)
#define REP(I,N) FOR((I),0,(N))
#define UP(I,A,B) for((I)=(A);(I)<=(B);(I)++)
#define DW(I,A,B) for((I)=(A);(I)>=(B);(I)--)
#define IN(P) cin>>(P)
#define IN2(P1,P2) cin>>(P1)>>(P2)
#define IN3(P1,P2,P3) cin>>(P1)>>(P2)>>(P3)
#define INS(I,N,V) REP((I),(N)) cin>>(V[I])
#define INS2(I,N,V1,V2) REP((I),(N)) cin>>(V1[I])>>(V2[I]);
#define INS3(I,N,V1,V2,V3) REP((I),(N)) cin>>(V1[I])>>(V2[I])>>(V3[I]);
#define OUT(P) cout<<(P)<<endl
#define OUT2(P1,P2) cout<<(P1)<<" "<<(P2)<<endl
#define OUT3(P1,P2,P3) cout<<(P1)<<" "<<(P2)<<" "<<(P3)<<endl
#define OUTS(I,N,V) REP((I),(N)) cout<<(V[i])<<endl
#define ALL(C) (C).begin(),(C).end()
#define RALL(C) (C).rbegin(),(C).rend()
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
template<class T>inline bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}
template<class T>inline bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}

string s[3];
inline void solve(){
  INS(i,3,s);
  REP(i,3)cout<<s[i][0];
  cout<<endl;
}

int main(int argc,char**argv){
  BEGIN
  solve();
  END
}


Compiler output:
a.cc: In function 'void solve()':
a.cc:30:7: error: 'i' was not declared in this scope
   30 |   INS(i,3,s);
      |       ^
a.cc:5:25: note: in definition of macro 'FOR'
    5 | #define FOR(I,A,B) for((I)=(A);(I)<(B);(I)++)
      |                         ^
a.cc:12:20: note: in expansion of macro 'REP'
   12 | #define INS(I,N,V) REP((I),(N)) cin>>(V[I])
      |                    ^~~
a.cc:30:3: note: in expansion of macro 'INS'
   30 |   INS(i,3,s);
      |   ^~~
a.cc:31:7: error: 'i' was not declared in this scope
   31 |   REP(i,3)cout<<s[i][0];
      |       ^
a.cc:5:25: note: in definition of macro 'FOR'
    5 | #define FOR(I,A,B) for((I)=(A);(I)<(B);(I)++)
      |                         ^
a.cc:31:3: note: in expansion of macro 'REP'
   31 |   REP(i,3)cout<<s[i][0];
      |   ^~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  string a,b,c;
  cin >> a>> c >> b;
  cout <<  A << c.at(0) <<  C << endl;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:7:12: error: 'A' was not declared in this scope
    7 |   cout <<  A << c.at(0) <<  C << endl;
      |            ^
a.cc:7:29: error: 'C' was not declared in this scope
    7 |   cout <<  A << c.at(0) <<  C << endl;
      |                             ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  string c;
  cin >> c;
  cout <<  A << c.at(0) <<  C << endl;
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:7:12: error: 'A' was not declared in this scope
    7 |   cout <<  A << c.at(0) <<  C << endl;
      |            ^
a.cc:7:29: error: 'C' was not declared in this scope
    7 |   cout <<  A << c.at(0) <<  C << endl;
      |                             ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main () {
  string s;
  cin >> s;
  
  cout << AtCoder.at(0) << s.at(0) << Contest.at(0) << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:11: error: 'AtCoder' was not declared in this scope
    8 |   cout << AtCoder.at(0) << s.at(0) << Contest.at(0) << endl;
      |           ^~~~~~~
a.cc:8:39: error: 'Contest' was not declared in this scope; did you mean 'const'?
    8 |   cout << AtCoder.at(0) << s.at(0) << Contest.at(0) << endl;
      |                                       ^~~~~~~
      |                                       const
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main () {
  string s;
  
  cout << A << s.at(0) << C << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:11: error: 'A' was not declared in this scope
    7 |   cout << A << s.at(0) << C << endl;
      |           ^
a.cc:7:27: error: 'C' was not declared in this scope
    7 |   cout << A << s.at(0) << C << endl;
      |                           ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  string a,b,c;
  cin >> a >>  b >> c;
  cout << A + b.at(0) + C << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:11: error: 'A' was not declared in this scope
    6 |   cout << A + b.at(0) + C << endl;
      |           ^
a.cc:6:25: error: 'C' was not declared in this scope
    6 |   cout << A + b.at(0) + C << endl;
      |                         ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  string a,b,c;
  cin >> a >>  b >> c;
  cout << A +'b.at(0)' + C << endl;
}

Compiler output:
a.cc:6:14: warning: multi-character literal with 7 characters exceeds 'int' size of 4 bytes
    6 |   cout << A +'b.at(0)' + C << endl;
      |              ^~~~~~~~~
a.cc: In function 'int main()':
a.cc:6:11: error: 'A' was not declared in this scope
    6 |   cout << A +'b.at(0)' + C << endl;
      |           ^
a.cc:6:26: error: 'C' was not declared in this scope
    6 |   cout << A +'b.at(0)' + C << endl;
      |                          ^
Language: C

#include<stdio.h>
int main (){
char a,b,c;
  scanf ("%s%s%s",a,b,c);
  printf("A%cC",b[0]);
return 0;
}


Compiler output:
main.c: In function 'main':
main.c:5:18: error: subscripted value is neither array nor pointer nor vector
    5 |   printf("A%cC",b[0]);
      |                  ^
Language: C++

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#define For(i, n) for(int i = 0; i < (n); i ++)
#define Range(c) c.begin(), c.end()
#define RevRange(c) c.begin(), c.end()
#define Cin(T, x) T x; cin >> x;
#define Cins(T, n, xs) vector<T> xs(n); For(i, n) cin >> xs[i];
#define Cout(val) cout << (val) << "\n";
#define Sort(a) sort(Range(a));
#define DeSort(a) sort(RevRange(a));

using namespace std;
using ll = long long;

int main(void){
    Cin(string, a);
    Cin(string, b);
    Cin(int, c);
    Cin(int, d);
    cout << "A" << b[0] << "C\n;
    //Cout(() ? "Yes" : "No");
    //Cout(() ? "YES" : "NO");
}

Compiler output:
a.cc:22:28: warning: missing terminating " character
   22 |     cout << "A" << b[0] << "C\n;
      |                            ^
a.cc:22:28: error: missing terminating " character
   22 |     cout << "A" << b[0] << "C\n;
      |                            ^~~~~
a.cc: In function 'int main()':
a.cc:25:1: error: expected primary-expression before '}' token
   25 | }
      | ^
Language: C++

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#define For(i, n) for(int i = 0; i < (n); i ++)
#define Range(c) c.begin(), c.end()
#define RevRange(c) c.begin(), c.end()
#define Cin(T, x) T x; cin >> x;
#define Cins(T, n, xs) vector<T> xs(n); For(i, n) cin >> xs[i];
#define Cout(val) cout << (val) << "\n";
#define Sort(a) sort(Range(a));
#define DeSort(a) sort(RevRange(a));

using namespace std;
using ll = long long;

int main(void){
    Cin(string, a);
    Cin(string, b);
    Cin(int, c);
    Cin(int, d);
    Cout("A" + b[0] + "C");
    //Cout(() ? "Yes" : "No");
    //Cout(() ? "YES" : "NO");
}

Compiler output:
a.cc: In function 'int main()':
a.cc:22:21: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
   22 |     Cout("A" + b[0] + "C");
      |                     ^ ~~~
      |                       |
      |                       const char [2]
a.cc:10:28: note: in definition of macro 'Cout'
   10 | #define Cout(val) cout << (val) << "\n";
      |                            ^~~
Language: C

#include <stdio.h>
int main(){
char s[116];
for (i=0;i<116;i++){
scanf("%c",&s[i]);
}
printf("A%cC\n",s[8]);
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:4:6: error: 'i' undeclared (first use in this function)
    4 | for (i=0;i<116;i++){
      |      ^
main.c:4:6: note: each undeclared identifier is reported only once for each function it appears in
Language: C

#include <stdio.h>
int main(){
char s[116];
for (i=0;i<116;i++){
scanf("%c",&s[1]);
}
printf("A%cC\n",s[8]);
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:4:6: error: 'i' undeclared (first use in this function)
    4 | for (i=0;i<116;i++){
      |      ^
main.c:4:6: note: each undeclared identifier is reported only once for each function it appears in
Language: C

#include <stdio.h>
int main(){
char s[116];
for (i=0;i<116;i++){
scans("%c",&s[1]);
}
printf("A%cC\n",s[8]);
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:4:6: error: 'i' undeclared (first use in this function)
    4 | for (i=0;i<116;i++){
      |      ^
main.c:4:6: note: each undeclared identifier is reported only once for each function it appears in
main.c:5:1: error: implicit declaration of function 'scans'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    5 | scans("%c",&s[1]);
      | ^~~~~
      | scanf
Language: C++

#include <bits/stdc++.h>
#include <unordered_map>
typedef long long ll;
#define rep(i,m,n) for(ll i = (m); i < (n); i++)
#define rrep(i,m,n) for(ll i = (m); i >= (n); i--)
#define print(x) cout << (x) << endl;
#define print2(x,y) cout << (x) << " " << (y) << endl;
#define printa(x,n) for(ll i = 0; i < n; i++){ cout << (x[i]) << " \n"[i == n-1];}
#define printp(x,n) for(ll i = 0; i < n; i++){ cout << "(" << x[i].first << ", " << x[i].second << ") "; } cout << endl;
#define INF (1e18)
using namespace std;
const ll MOD = 1e9 + 7;
typedef pair<ll, ll> lpair;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    string s[3];
    rep(i,0,3) cin >> s[0];
    print("A" + s[1][0] + "C");

}


Compiler output:
a.cc: In function 'int main()':
a.cc:20:25: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
   20 |     print("A" + s[1][0] + "C");
      |                         ^ ~~~
      |                           |
      |                           const char [2]
a.cc:6:27: note: in definition of macro 'print'
    6 | #define print(x) cout << (x) << endl;
      |                           ^
Language: C++

#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<ctime>
#include<cstdio>
#include<string>
//#include<string>
//#include<sstream>
using namespace std;

int main()
{
	char a[1000];
	gets(a);
	printf("A%cC\n",a[8]+32);
	//cout<<"A"<<(char)(a[8])<<"C"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
   16 |         gets(a);
      |         ^~~~
      |         getw
Language: C++

#include<iostream>
using namespace std;

int main()
{
    string s;

    for(int i = 0;i < 3;i++){
        cin >> s;
        if(i == 1) char ans = s[0];
    }
    cout << "A" << ans << "C" << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:12:20: error: 'ans' was not declared in this scope; did you mean 'abs'?
   12 |     cout << "A" << ans << "C" << endl;
      |                    ^~~
      |                    abs
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string str;
  cin >> str;

char b = str.at(0);
cout << "A" + b + "C" << endl;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:9:17: error: invalid operands of types 'const char*' and 'const char [2]' to binary 'operator+'
    9 | cout << "A" + b + "C" << endl;
      |         ~~~~~~~ ^ ~~~
      |             |     |
      |             |     const char [2]
      |             const char*
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string str;
  cin >> str;

string b = str.at(0);
string a = "A";
a += b;
a += 'C';
cout << a << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:18: error: conversion from '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
    8 | string b = str.at(0);
      |            ~~~~~~^~~
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string str;
  cin >> str;

char b = str.at(0);
cout << A+b+C << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:9: error: 'A' was not declared in this scope
    9 | cout << A+b+C << endl;
      |         ^
a.cc:9:13: error: 'C' was not declared in this scope
    9 | cout << A+b+C << endl;
      |             ^
Language: C++

#include<iostream>
using namespace std;

int main( )
{
  string s;
  cin >> AtCoder >> s >> Contest;

  cout << "A" << s.at(0) << "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:10: error: 'AtCoder' was not declared in this scope
    7 |   cin >> AtCoder >> s >> Contest;
      |          ^~~~~~~
a.cc:7:26: error: 'Contest' was not declared in this scope; did you mean 'const'?
    7 |   cin >> AtCoder >> s >> Contest;
      |                          ^~~~~~~
      |                          const
Language: C++

#include <stdio.h>
int main(void){
  char c;
  scanf("Atcoder %c",&c);
  printf("A%cC\n",c);
  return 0;

Compiler output:
a.cc: In function 'int main()':
a.cc:6:12: error: expected '}' at end of input
    6 |   return 0;
      |            ^
a.cc:2:15: note: to match this '{'
    2 | int main(void){
      |               ^
Language: C++

#include <iostream>

using namespace std;

int main()
{
  char s[];
  cin >>  s[];
  
  cout << "A" << s[0] << "B\n";
}

  

Compiler output:
a.cc: In function 'int main()':
a.cc:7:8: error: storage size of 's' isn't known
    7 |   char s[];
      |        ^
a.cc:8:13: error: expected primary-expression before ']' token
    8 |   cin >>  s[];
      |             ^
Language: C

#include <stdio.h>
int main(void)
{
	char s[];
	scanf("%s", &s);
	printf("A%cC", s[0]);
	
	return 0;
}
	

		
	

Compiler output:
main.c: In function 'main':
main.c:4:14: error: array size missing in 's'
    4 |         char s[];
      |              ^
Language: C

#include <stdio.h>
#include <iostream>
#include <string>
int main(void)
{
	char s[100];
	scanf("%c", &s);
	printf("A%cC", s[0]);
	
	return 0;
}
	

		
	

Compiler output:
main.c:2:10: fatal error: iostream: No such file or directory
    2 | #include <iostream>
      |          ^~~~~~~~~~
compilation terminated.
Language: C++

#include<iostream>
#include<string>
 
usingn namespace std;
 
int main(){
 
 string temp1,temp2;
 	cin  >> temp1;
  	cin >>temp2;
  	cin  >> temp1;
  
  cout<<"A" <<temp2[0]<<"C"<<endl;
 
}


Compiler output:
a.cc:4:1: error: 'usingn' does not name a type
    4 | usingn namespace std;
      | ^~~~~~
a.cc: In function 'int main()':
a.cc:8:2: error: 'string' was not declared in this scope
    8 |  string temp1,temp2;
      |  ^~~~~~
a.cc:8:2: note: suggested alternatives:
In file included from /usr/include/c++/14/iosfwd:41,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
In file included from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:9:9: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    9 |         cin  >> temp1;
      |         ^~~
      |         std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:9:17: error: 'temp1' was not declared in this scope
    9 |         cin  >> temp1;
      |                 ^~~~~
a.cc:10:15: error: 'temp2' was not declared in this scope
   10 |         cin >>temp2;
      |               ^~~~~
a.cc:13:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   13 |   cout<<"A" <<temp2[0]<<"C"<<endl;
      |   ^~~~
      |   std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:13:30: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   13 |   cout<<"A" <<temp2[0]<<"C"<<endl;
      |                              ^~~~
      |                              std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
Language: C++

#include<iostream>
#include<string>

usingn namespace std;

int main(){
  
  string temp1,temp2;
 	cin  >> temp1;
  	cin >>temp2;
  	cin  >> temp1;
  
  cout<<A <<temp2[0]<<C<<endl;
  
  
}

Compiler output:
a.cc:4:1: error: 'usingn' does not name a type
    4 | usingn namespace std;
      | ^~~~~~
a.cc: In function 'int main()':
a.cc:8:3: error: 'string' was not declared in this scope
    8 |   string temp1,temp2;
      |   ^~~~~~
a.cc:8:3: note: suggested alternatives:
In file included from /usr/include/c++/14/iosfwd:41,
                 from /usr/include/c++/14/ios:40,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
In file included from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44:
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:9:9: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    9 |         cin  >> temp1;
      |         ^~~
      |         std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:9:17: error: 'temp1' was not declared in this scope
    9 |         cin  >> temp1;
      |                 ^~~~~
a.cc:10:15: error: 'temp2' was not declared in this scope
   10 |         cin >>temp2;
      |               ^~~~~
a.cc:13:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   13 |   cout<<A <<temp2[0]<<C<<endl;
      |   ^~~~
      |   std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:13:9: error: 'A' was not declared in this scope
   13 |   cout<<A <<temp2[0]<<C<<endl;
      |         ^
a.cc:13:23: error: 'C' was not declared in this scope
   13 |   cout<<A <<temp2[0]<<C<<endl;
      |                       ^
a.cc:13:26: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   13 |   cout<<A <<temp2[0]<<C<<endl;
      |                          ^~~~
      |                          std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(void){
	
	string S;
	cin >> S;
	cout << A << S.at(0) << C << endl;
	return 0;
	
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:17: error: 'A' was not declared in this scope
    7 |         cout << A << S.at(0) << C << endl;
      |                 ^
a.cc:7:33: error: 'C' was not declared in this scope
    7 |         cout << A << S.at(0) << C << endl;
      |                                 ^
Language: C++

#include<bits/stdc++>
using namespace std;
int main(void){
	
	string S;
	cin >> S;
	cout << A << S.at(0) << C << endl;
	return 0;
	
}

Compiler output:
a.cc:1:9: fatal error: bits/stdc++: No such file or directory
    1 | #include<bits/stdc++>
      |         ^~~~~~~~~~~~~
compilation terminated.
Language: C++

#include<iostream>
#include<string>

using namespace std;

int main(){
  String A,B,C;
  cin>>A>>B>>C;
  
  cout<<A[0]<<B[0]<<C[0]<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:3: error: 'String' was not declared in this scope
    7 |   String A,B,C;
      |   ^~~~~~
a.cc:8:8: error: 'A' was not declared in this scope
    8 |   cin>>A>>B>>C;
      |        ^
a.cc:8:11: error: 'B' was not declared in this scope
    8 |   cin>>A>>B>>C;
      |           ^
a.cc:8:14: error: 'C' was not declared in this scope
    8 |   cin>>A>>B>>C;
      |              ^
Language: C++

# include <bits/stdc++.h>
# define rep(i, n) for(int i=0, i##_len=(n); i<i##_len; ++i)
# define reps(i, n) for(int i=1, i##_len=(n); i<=i##_len; ++i)
# define rrep(i, n) for(int i=((int)(n)-1); i>=0; --i)
# define rreps(i, n) for(int i=((int)(n)); i>0; --i)
# define ALL(x) (x).begin(), (x).end()
# define SZ(x) ((int)(x).size())
# define pb push_back
# define optimize_cin() cin.tie(0); ios::sync_with_stdio(false)
using namespace std;
using lint = long long;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

int main()
{
    String s; cin >> s;

    cout << "A" << s[0] << "C" << "\n";

    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:17:5: error: 'String' was not declared in this scope
   17 |     String s; cin >> s;
      |     ^~~~~~
a.cc:17:22: error: 's' was not declared in this scope
   17 |     String s; cin >> s;
      |                      ^
Language: C++

#inlcude <iostream>
#include <string>

using namespace std;

int main(void){
  string s1,s2,s3;
  
  cin >> s1 >> s2 >> s3;
  
  cout << "A" << s2[0] << "C" << endl;
  return 0;
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #inlcude; did you mean #include?
    1 | #inlcude <iostream>
      |  ^~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:9:3: error: 'cin' was not declared in this scope
    9 |   cin >> s1 >> s2 >> s3;
      |   ^~~
a.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    2 | #include <string>
  +++ |+#include <iostream>
    3 | 
a.cc:11:3: error: 'cout' was not declared in this scope
   11 |   cout << "A" << s2[0] << "C" << endl;
      |   ^~~~
a.cc:11:3: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:11:34: error: 'endl' was not declared in this scope
   11 |   cout << "A" << s2[0] << "C" << endl;
      |                                  ^~~~
a.cc:3:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    2 | #include <string>
  +++ |+#include <ostream>
    3 |
Language: C++

#inlcude <iostream>
#include <string>

using namespace std;

int main(void){
  string s;
  
  cin >> s;
  
  cout << "A" << s[0] << "C" << endl;
  return 0;
}


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #inlcude; did you mean #include?
    1 | #inlcude <iostream>
      |  ^~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:9:3: error: 'cin' was not declared in this scope
    9 |   cin >> s;
      |   ^~~
a.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    2 | #include <string>
  +++ |+#include <iostream>
    3 | 
a.cc:11:3: error: 'cout' was not declared in this scope
   11 |   cout << "A" << s[0] << "C" << endl;
      |   ^~~~
a.cc:11:3: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:11:33: error: 'endl' was not declared in this scope
   11 |   cout << "A" << s[0] << "C" << endl;
      |                                 ^~~~
a.cc:3:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    2 | #include <string>
  +++ |+#include <ostream>
    3 |
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string a,b,c;
  cin >> a >> b >> c;
  char B = b.st(0);
     cout << "A" << b << "C"<< endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:14: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'st'; did you mean 'at'?
    7 |   char B = b.st(0);
      |              ^~
      |              at
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string a,b,c;
  cin >> a >> b >> c;
  char a,b,c;
     cout << "A" << b << "C"<< endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:8: error: conflicting declaration 'char a'
    7 |   char a,b,c;
      |        ^
a.cc:5:10: note: previous declaration as 'std::string a'
    5 |   string a,b,c;
      |          ^
a.cc:7:10: error: conflicting declaration 'char b'
    7 |   char a,b,c;
      |          ^
a.cc:5:12: note: previous declaration as 'std::string b'
    5 |   string a,b,c;
      |            ^
a.cc:7:12: error: conflicting declaration 'char c'
    7 |   char a,b,c;
      |            ^
a.cc:5:14: note: previous declaration as 'std::string c'
    5 |   string a,b,c;
      |              ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  string s;
  cin >> s;
  char a;
  for(int i = 0;i < s.size();i++){
       if(s.at(i) == " "){
        a = s.at(i+1);
        break;
        }
    }
     cout << "A" << a << "C"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:19: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
    9 |        if(s.at(i) == " "){
      |           ~~~~~~~~^~~~~~
Language: C++

#include <bits/stdc++;>
using namespace std;

int main(){
  string s;
  cin >> s;
  char a;
  for(int i = 0;i < s.size();i++){
       if(s.at(i) == " "){
        a = s.at(i+1);
        break;
        }
    }
     cout << "A" << a << "C"<<endl;
}

Compiler output:
a.cc:1:10: fatal error: bits/stdc++;: No such file or directory
    1 | #include <bits/stdc++;>
      |          ^~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
string S;
  
  cout<<A<<S.at(0)<<C<<endl;

}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'A' was not declared in this scope
    7 |   cout<<A<<S.at(0)<<C<<endl;
      |         ^
a.cc:7:21: error: 'C' was not declared in this scope
    7 |   cout<<A<<S.at(0)<<C<<endl;
      |                     ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
string S;
  
  cout<<A<<S[0]<<C<<endl;

}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'A' was not declared in this scope
    7 |   cout<<A<<S[0]<<C<<endl;
      |         ^
a.cc:7:18: error: 'C' was not declared in this scope
    7 |   cout<<A<<S[0]<<C<<endl;
      |                  ^
Language: C++

#include <iostream>
#include <string>
using namespace std;

int main() {
  string a, b, c;
  cin >> a >> b >> c;
  
  cout << 'a[0]' + 'b[0]' + c[0]';
  return 0;
}

Compiler output:
a.cc:9:11: warning: multi-character character constant [-Wmultichar]
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |           ^~~~~~
a.cc:9:20: warning: multi-character character constant [-Wmultichar]
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |                    ^~~~~~
a.cc:9:33: warning: missing terminating ' character
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |                                 ^
a.cc:9:33: error: missing terminating ' character
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |                                 ^~
a.cc: In function 'int main()':
a.cc:9:18: warning: integer overflow in expression of type 'int' results in '-1011457862' [-Woverflow]
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |           ~~~~~~~^~~~~~~~
a.cc:9:33: error: expected ';' before 'return'
    9 |   cout << 'a[0]' + 'b[0]' + c[0]';
      |                                 ^
      |                                 ;
   10 |   return 0;
      |   ~~~~~~
Language: C

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <algorithm>
using namespace std;
int main(){
    char a[1005];
    int k = 0,len;
    while(~scanf("%s",a)){
        printf("%c",a[0]);
    	memset(a,0,sizeof(a));
	}
    return 0;
    }

Compiler output:
main.c:4:10: fatal error: algorithm: No such file or directory
    4 | #include <algorithm>
      |          ^~~~~~~~~~~
compilation terminated.
Language: C++

#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <string.h>
using namespace std;
int main(){
	char a[1005];
	int len,k;
	gets(a);
	len = strlen(a);
	for( k = 0; k <= len; k++){
		if( a[k] >= 65 && a[k] <= 90){
			printf("%c",a[k]);
			}
		}
		return 0;
	}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
    9 |         gets(a);
      |         ^~~~
      |         getw
Language: C

#include<stdio.h>

int main(){
  char Atcoder[100], s[100], Contest[100], a[4];
  
  scanf("%s %s %s", Atcoder, s , Contest);
  
  a[0] = Atcoder[0];
  a[1] = s[0];
  c[2] = Contest[0];
  a[3] = 0;
  
  printf("%s\n", a);
  
}

Compiler output:
main.c: In function 'main':
main.c:10:3: error: 'c' undeclared (first use in this function)
   10 |   c[2] = Contest[0];
      |   ^
main.c:10:3: note: each undeclared identifier is reported only once for each function it appears in
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  strung A,B,C ;
  cin >> A >> B >> C;
  cout << "A" << B.at(0) << "C" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:5:3: error: 'strung' was not declared in this scope; did you mean 'trunc'?
    5 |   strung A,B,C ;
      |   ^~~~~~
      |   trunc
a.cc:6:10: error: 'A' was not declared in this scope
    6 |   cin >> A >> B >> C;
      |          ^
a.cc:6:15: error: 'B' was not declared in this scope
    6 |   cin >> A >> B >> C;
      |               ^
a.cc:6:20: error: 'C' was not declared in this scope
    6 |   cin >> A >> B >> C;
      |                    ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string str;
  cin >> srt;

  char x = str.at(0);

  cout << "A" << x << "C" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:10: error: 'srt' was not declared in this scope; did you mean 'str'?
    6 |   cin >> srt;
      |          ^~~
      |          str
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  string s;
  cin >> s;
  
  s.at(8) = x;

  cout << "A" << x << "C" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:13: error: 'x' was not declared in this scope
    8 |   s.at(8) = x;
      |             ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string s;
  cin >> s;
  cout << A << s[0] << C << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:11: error: 'A' was not declared in this scope
    6 |   cout << A << s[0] << C << endl;
      |           ^
a.cc:6:24: error: 'C' was not declared in this scope
    6 |   cout << A << s[0] << C << endl;
      |                        ^