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

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

int main()
{
  string s;
  cin >> s;
  for (int i = 2; i < s.length; i += 2) {
    s[i] = '\0';
  }
  cout << s << endl;
  
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:25: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::length() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
    9 |   for (int i = 2; i < s.length; i += 2) {
      |                       ~~^~~~~~
      |                               ()
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string s; cin>>s;
  for(int i=0;i<s.size()/2+1;i+=2){
    cout<<s[i];
  }
  endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:7: error: statement cannot resolve address of overloaded function
    8 |   endl;
      |       ^
Language: C++

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

int main(){
  string S;
  
  cin>>S;
  
  int K;
  
  if(S.size()%2==0){
    K=S.size()/2;
  }
  else if(S.size()%2!=0){
    K=S.size()/2+1
  }
  
  vector<char> ans(K);

  
  for(int i=0;i<S.size();i++){
if(i%2!=0){
  ans.at(i)=S.at(i);
}
  }
  
  for(int i=0;i<K;i++){
cout<<ans.at(i);
  }
}

  

Compiler output:
a.cc: In function 'int main()':
a.cc:15:19: error: expected ';' before '}' token
   15 |     K=S.size()/2+1
      |                   ^
      |                   ;
   16 |   }
      |   ~
Language: C++

#include<iostream>
#include<string>

int main(){
  int i;
  string s;
  
  cin>>s;
  
  for(i=0;i<s.size();i+=2)
    cout<<s[i];
  cout<<endl;
  return 0;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:3: error: 'string' was not declared in this scope
    6 |   string s;
      |   ^~~~~~
a.cc:6:3: 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:8:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 |   cin>>s;
      |   ^~~
      |   std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:8:8: error: 's' was not declared in this scope
    8 |   cin>>s;
      |        ^
a.cc:11:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |     cout<<s[i];
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:12:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 |   cout<<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:12:9: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   12 |   cout<<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>
using namespace std;

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

    for(int i = 0; i < s.size(); i += 2) {
        cout << s[i];
    }

    cout << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:26: error: request for member 'size' in 's', which is of non-class type 'int'
    9 |     for(int i = 0; i < s.size(); i += 2) {
      |                          ^~~~
a.cc:10:18: error: invalid types 'int[int]' for array subscript
   10 |         cout << s[i];
      |                  ^
Language: C++

#include<bits/stdc++.h>

using namespace std;


#define mod(cans) cans%10**9+7
#define cin_pl(x,y) for(int i=0;i<x;i++){cin>>y[i];}
#define pl_twin(x,y,z) for(int i=0;i<x;i++){cin>>y[i]>>z[i];}
#define debug(x) cout << "Debug" << x << "\n"
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
//#define st(s) size_t size = s.length()
#define prians(Answer) cout<<Answer<<"\n"
#define make_pair mp;
#define com_div(x,Co) for(int i=1;i<x+1;i++){if(x%i==0){Co++;}}
#define TF(X) X==1?cout<<"Yes\n":cout<<"No\n"
#define elcon else{continue;}

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<vector<int>> matrix;
typedef pair<int,int> pr;
typedef vector<pr> vpt;
typedef greater<int> gi;

int main()
{
   string s;
	cin>>s;
	size_t size =s.length();
	rep(i,size)
	{
	if(i%2==0)
	{
	s.erace(i);
}
	}
    prians(s);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:38:11: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'erace'; did you mean 'erase'?
   38 |         s.erace(i);
      |           ^~~~~
      |           erase
Language: C++

#include<bits/stdc++.h>

using namespace std;


#define mod(cans) cans%10**9+7
#define cin_pl(x,y) for(int i=0;i<x;i++){cin>>y[i];}
#define pl_twin(x,y,z) for(int i=0;i<x;i++){cin>>y[i]>>z[i];}
#define debug(x) cout << "Debug" << x << "\n"
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
//#define st(s) size_t size = s.length()
#define prians(Answer) cout<<Answer<<"\n"
#define make_pair mp;
#define com_div(x,Co) for(int i=1;i<x+1;i++){if(x%i==0){Co++;}}
#define TF(X) X==1?cout<<"Yes\n":cout<<"No\n"
#define elcon else{continue;}

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<vector<int>> matrix;
typedef pair<int,int> pr;
typedef vector<pr> vpt;
typedef greater<int> gi;

int main()
{
   string s;
	cin>>s;
	size_t size =s.length();
	rep(i,size)
	{
	if(i%2==0)
	{
	str.erace(i);
}
	}
    prians(s);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:38:9: error: 'str' was not declared in this scope; did you mean 'std'?
   38 |         str.erace(i);
      |         ^~~
      |         std
Language: C++

#include<iostream>
#include<algorithm>
#include<iterator>
#include<vector>
#include<string>
#include<map>

using namespace std;


#define mod(cans) cans%10**9+7
#define cin_pl(x,y) for(int i=0;i<x;i++){cin>>y[i];}
#define pl_twin(x,y,z) for(int i=0;i<x;i++){cin>>y[i]>>z[i];}
#define debug(x) cout << "Debug" << x << "\n"
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
//#define st(s) size_t size = s.length()
#define prians(Answer) cout<<Answer<<"\n"
#define make_pair mp;
#define com_div(x,Co) for(int i=1;i<x+1;i++){if(x%i==0){Co++;}}
#define TF(X) X==1?cout<<"Yes\n":cout<<"No\n"
#define elcon else{continue;}

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<vector<int>> matrix;
typedef pair<int,int> pr;
typedef vector<pr> vpt;
typedef greater<int> gi;

int main()
{
   string s;
	cin>>s;
	size_t size =s.length();
	rep(i,size)
	{
	if(i%2==0)
	{
	str.erase(s[i]);
}
	}
    prians(s);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:43:9: error: 'str' was not declared in this scope; did you mean 'std'?
   43 |         str.erase(s[i]);
      |         ^~~
      |         std
Language: C++

#include<iostream>
#include<algorithm>
#include<iterator>
#include<vector>
#include<string>
#include<map>

using namespace std;


#define mod(cans) cans%10**9+7
#define cin_pl(x,y) for(int i=0;i<x;i++){cin>>y[i];}
#define pl_twin(x,y,z) for(int i=0;i<x;i++){cin>>y[i]>>z[i];}
#define debug(x) cout << "Debug" << x << "\n"
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
//#define st(s) size_t size = s.length()
#define prians(Answer) cout<<Answer<<"\n"
#define make_pair mp;
#define com_div(x,Co) for(int i=1;i<x+1;i++){if(x%i==0){Co++;}}
#define TF(X) X==1?cout<<"Yes\n":cout<<"No\n"
#define elcon else{continue;}

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<vector<int>> matrix;
typedef pair<int,int> pr;
typedef vector<pr> vpt;
typedef greater<int> gi;

int main()
{
   string s;
	cin>>s;
	size_t size =s.length();
	rep(i,size)
	{
	if(i%2==0)
	{
	str.erace(s[i]);
}
	}
    prians(s);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:43:9: error: 'str' was not declared in this scope; did you mean 'std'?
   43 |         str.erace(s[i]);
      |         ^~~
      |         std
Language: C++

#include<iostream>
#include<algorithm>
#include<iterator>
#include<vector>
#include<string>
#include<map>

using namespace std;


#define mod(cans) cans%10**9+7
#define cin_pl(x,y) for(int i=0;i<x;i++){cin>>y[i];}
#define pl_twin(x,y,z) for(int i=0;i<x;i++){cin>>y[i]>>z[i];}
#define debug(x) cout << "Debug" << x << "\n"
#define rep(i,n) for(int i=0;i<n;i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
//#define st(s) size_t size = s.length()
#define prians(Answer) cout<<Answer<<"\n"
#define make_pair mp;
#define com_div(x,Co) for(int i=1;i<x+1;i++){if(x%i==0){Co++;}}
#define TF(X) X==1?cout<<"Yes\n":cout<<"No\n"
#define elcon else{continue;}

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<string> vs;
typedef vector<vector<int>> matrix;
typedef pair<int,int> pr;
typedef vector<pr> vpt;
typedef greater<int> gi;

int main()
{
   string s;
	cin>>s;
	size_t size =s.length();
	rep(i,size)
	{
	if(i%2==0)
	{
	str.erace(s[i])
}
	}
    prians(s);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:43:9: error: 'str' was not declared in this scope; did you mean 'std'?
   43 |         str.erace(s[i])
      |         ^~~
      |         std
Language: C++

#include<iostream>
#include<string>
#include<vector>
#include<utility>
#include<algorithm>
#include<cmath>
#include<climits>
using namespace std;

int main(){
	srting s;
	cin >> s;
	for(int i = 0; i < s.size(); i += 2)
		cout << s[i];
	cout << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:9: error: 'srting' was not declared in this scope
   11 |         srting s;
      |         ^~~~~~
a.cc:12:16: error: 's' was not declared in this scope
   12 |         cin >> s;
      |                ^
Language: C++

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

int main(void) {
    char s[100010] = {};
	scanf("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:20: error: 'strlen' was not declared in this scope
    9 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:4:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    3 | #include <stdlib.h>
  +++ |+#include <cstring>
    4 | using namespace std;
Language: C++

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

int main(void) {
    char s[100010] = {};
	scanf("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:20: error: 'strlen' was not declared in this scope
    8 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include <iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

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

char s[100010];

int main(void) {
	scanf("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:20: error: 'strlen' was not declared in this scope
    9 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include <iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

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

int main(void) {
	char s[100000];
	scanf("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:20: error: 'strlen' was not declared in this scope
    8 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include <iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

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

int main() {
	char s[100000];
	scanf("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:20: error: 'strlen' was not declared in this scope
    8 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include <iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

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

int main() {
	char s[100000];
	scanf_s("%s", s);
	int size = strlen(s);
	for (int i = 0; i < size; i += 2)cout << s[i];
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'scanf_s' was not declared in this scope; did you mean 'scanf'?
    7 |         scanf_s("%s", s);
      |         ^~~~~~~
      |         scanf
a.cc:8:20: error: 'strlen' was not declared in this scope
    8 |         int size = strlen(s);
      |                    ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include <iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

#include <iostream>
#include <algorithm>
#include <string>
#include <math.h>
#include <stdio.h>
#include <set>
#include <vector>
using namespace std;


int main(){
    string s;
    cin>>s;
    int i=1;
    for(auto v:s){
        if(i%2==1){
            cout<<v;
        }
        i++
    }
    cout<<endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:12: error: expected ';' before '}' token
   19 |         i++
      |            ^
      |            ;
   20 |     }
      |     ~
Language: C++

#include <iostream>
#include <algorithm>
#include <string>
#include <math.h>
#include <stdio.h>
#include <set>
#include <vector>
using namespace std;


int main(){
    string s;
    cin>>s;
    int i=1;
    for(auto v:s){
        if(i=1){
            cout<<v;
        }
        i++
    }
    cout<<endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:12: error: expected ';' before '}' token
   19 |         i++
      |            ^
      |            ;
   20 |     }
      |     ~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string S;
  cin >> S;
  int a= S.size();
  for(int i=0;i<a/2;i++){
    cout << S.at(2i);
  }
  cout << endl;
  return 0;
}
    
  

Compiler output:
a.cc: In function 'int main()':
a.cc:8:17: error: no matching function for call to 'std::__cxx11::basic_string<char>::at(std::complex<double>)'
    8 |     cout << S.at(2i);
      |             ~~~~^~~~
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_string.h:1287:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::const_reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; const_reference = const char&; size_type = long unsigned int]'
 1287 |       at(size_type __n) const
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1287:20: note:   no known conversion for argument 1 from 'std::complex<double>' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1287 |       at(size_type __n) const
      |          ~~~~~~~~~~^~~
/usr/include/c++/14/bits/basic_string.h:1309:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; reference = char&; size_type = long unsigned int]'
 1309 |       at(size_type __n)
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1309:20: note:   no known conversion for argument 1 from 'std::complex<double>' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1309 |       at(size_type __n)
      |          ~~~~~~~~~~^~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string S;
  cin >> S;
  int a= S.size();
  for(i=0;i<a;i++){
    cout << S.at(2i);
  }
  cout << endl;
  return 0;
}
    
  

Compiler output:
a.cc: In function 'int main()':
a.cc:7:7: error: 'i' was not declared in this scope
    7 |   for(i=0;i<a;i++){
      |       ^
a.cc:8:17: error: no matching function for call to 'std::__cxx11::basic_string<char>::at(std::complex<double>)'
    8 |     cout << S.at(2i);
      |             ~~~~^~~~
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_string.h:1287:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::const_reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; const_reference = const char&; size_type = long unsigned int]'
 1287 |       at(size_type __n) const
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1287:20: note:   no known conversion for argument 1 from 'std::complex<double>' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1287 |       at(size_type __n) const
      |          ~~~~~~~~~~^~~
/usr/include/c++/14/bits/basic_string.h:1309:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::reference std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::at(size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; reference = char&; size_type = long unsigned int]'
 1309 |       at(size_type __n)
      |       ^~
/usr/include/c++/14/bits/basic_string.h:1309:20: note:   no known conversion for argument 1 from 'std::complex<double>' to 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'}
 1309 |       at(size_type __n)
      |          ~~~~~~~~~~^~~
Language: C++

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

int main () {
  string s ;
  cin >> s ;
  for(i=0;i<s.size();i++){
    cout << s.at(i*2);
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:7: error: 'i' was not declared in this scope
    7 |   for(i=0;i<s.size();i++){
      |       ^
Language: C++

#include <iostream>

int main(){
    string s;
    std::cin >> s;

    string ans;

    for(int i=0; i < s.size(); i++){
        if(i%2 == 1) ans += s[i];
    }
    std::cout << ans << std::endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:5: error: 'string' was not declared in this scope
    4 |     string s;
      |     ^~~~~~
a.cc:4:5: 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:5:17: error: 's' was not declared in this scope
    5 |     std::cin >> s;
      |                 ^
a.cc:7:11: error: expected ';' before 'ans'
    7 |     string ans;
      |           ^~~~
      |           ;
a.cc:10:22: error: 'ans' was not declared in this scope; did you mean 'abs'?
   10 |         if(i%2 == 1) ans += s[i];
      |                      ^~~
      |                      abs
a.cc:12:18: error: 'ans' was not declared in this scope; did you mean 'abs'?
   12 |     std::cout << ans << std::endl;
      |                  ^~~
      |                  abs
Language: C++

#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < n; i++)
using namespace std;
using ll = long long;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s;
  cin >> s;
  string ans = '';
  for(int i = 0; i < s.size(); i += 2) {
    ans.push_back(s[i]);
  }
  cout << ans << endl;

  return 0;
}

Compiler output:
a.cc:11:16: error: empty character constant
   11 |   string ans = '';
      |                ^~
a.cc: In function 'int main()':
a.cc:11:16: error: conversion from 'char' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
Language: C++

#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < n; i++)
using namespace std;
using ll = long long;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  string s;
  cin >> s;
  string ans = '';
  for(int i = 0; i < count; i += 2) {
    ans.push_back(s[i]);
  }
  cout << ans << endl;

  return 0;
}

Compiler output:
a.cc:11:16: error: empty character constant
   11 |   string ans = '';
      |                ^~
a.cc: In function 'int main()':
a.cc:11:16: error: conversion from 'char' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
a.cc:12:20: error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<'
   12 |   for(int i = 0; i < count; i += 2) {
      |                  ~~^~~~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
const long long mod = pow(10, 9) + 7;
const long long INF = 1LL << 60;
template <class T> bool chmin(T& a, T b){if (a > b) {a = b; return true;} return false;}
template <class T> bool chmax(T& a, T b){if (a < b) {a = b; return true;} return false;}
int divCeil(int A, int B) {return (A + (B - 1)) / B;}
long long divCeil(long long A, int B) {return (A + (B - 1)) / B;}
long long divCeil(int A, long long B) {return (A + (B - 1)) / B;}
long long divCeil(long long A, long long B) {return (A + (B - 1)) / B;}

int main()
{
  int s;
  cin >> s;
  int N = s.size();
  
  for (int i = 0; i < N; i += 2) cout << s.at(i);
  cout << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:13: error: request for member 'size' in 's', which is of non-class type 'int'
   16 |   int N = s.size();
      |             ^~~~
a.cc:18:44: error: request for member 'at' in 's', which is of non-class type 'int'
   18 |   for (int i = 0; i < N; i += 2) cout << s.at(i);
      |                                            ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
char s[100010];
int main()
{    
    gets(s);
    for(int i=0;i<strlen(s);i+=2)
    {
        cout<<s[i];
    }
    printf("\n");
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:5: error: 'gets' was not declared in this scope; did you mean 'getw'?
    6 |     gets(s);
      |     ^~~~
      |     getw
Language: C++

#include <bits/stdc++.h>
using namespace std;
char c;
int i=0;
int main()
{
    while(cin>>c){
        i++;
        if(i==1) (cout<<c;i=0;)
    }
    cout<<endl;
    return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:9:26: error: expected ')' before ';' token
    9 |         if(i==1) (cout<<c;i=0;)
      |                  ~       ^
      |                          )
a.cc:9:31: error: expected primary-expression before ')' token
    9 |         if(i==1) (cout<<c;i=0;)
      |                               ^
Language: C++

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

int main(){
  string s;
  for(int i=1;i<=s.size();i++){
    if(i%2==1)
      cout <<s[i];
  }
  cout <<ensl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:10: error: 'ensl' was not declared in this scope
   10 |   cout <<ensl;
      |          ^~~~
Language: C++

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

int main() {
	string s;
	cin >> s;
	string ans;
	for (int i = 0; i < s.size(); i+=2) {
			ans += s.at(i);
	}
	cout << ans << endl;

Compiler output:
a.cc: In function 'int main()':
a.cc:11:29: error: expected '}' at end of input
   11 |         cout << ans << endl;
      |                             ^
a.cc:4:12: note: to match this '{'
    4 | int main() {
      |            ^
Language: C++

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

int main() {
    string s;
    cin >> s;
    for (int i=0; i<s.size(); i++) {
        if ((i + 1) % 2 != 0) cout << s[i];
    }
    cout << endl;

    return 0;
}


Compiler output:
a.cc:1:1: error: 'include' does not name a type
    1 | include <bits/stdc++.h>
      | ^~~~~~~
a.cc: In function 'int main()':
a.cc:5:5: error: 'string' was not declared in this scope
    5 |     string s;
      |     ^~~~~~
a.cc:6:5: error: 'cin' was not declared in this scope
    6 |     cin >> s;
      |     ^~~
a.cc:6:12: error: 's' was not declared in this scope
    6 |     cin >> s;
      |            ^
a.cc:8:31: error: 'cout' was not declared in this scope
    8 |         if ((i + 1) % 2 != 0) cout << s[i];
      |                               ^~~~
a.cc:10:5: error: 'cout' was not declared in this scope
   10 |     cout << endl;
      |     ^~~~
a.cc:10:13: error: 'endl' was not declared in this scope
   10 |     cout << endl;
      |             ^~~~
Language: C

#include <stdio.h>
int main(void){
char s[100005];
  scanf("%s",s);
  for(count=1;;count+2){
  printf("%c",s[count]);
    if(s[count+1]=='\0'||s[count+2]=='\0'){break;}
  }
  
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:5:7: error: 'count' undeclared (first use in this function)
    5 |   for(count=1;;count+2){
      |       ^~~~~
main.c:5:7: 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(){
  string s;
  cin>>s;
  for(int i=0;i<N/2;i++){
    cout<<s[2*i];
  }
  cout<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:17: error: 'N' was not declared in this scope
    6 |   for(int i=0;i<N/2;i++){
      |                 ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  string s;
  cin >> s;
  int N = s.size();
  string ans;
  for(int i = 0;i< N; i+= 2){
    ans += s[i]
  }
  cout << ans << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:16: error: expected ';' before '}' token
    9 |     ans += s[i]
      |                ^
      |                ;
   10 |   }
      |   ~
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main() {
	string str;
	cin>>str;
	int k;
	if(k%2==0){
	for(int i=0; i<(str.size())/2){
		cout<<string.at(2*i)<<endl;
		}
	}
	else{
		for(int i=0; i<(str.size())/2+1){
		cout<<string.at(2*i)<<endl;
	}
	}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:38: error: expected ';' before ')' token
    8 |         for(int i=0; i<(str.size())/2){
      |                                      ^
      |                                      ;
a.cc:9:29: error: expected primary-expression before '.' token
    9 |                 cout<<string.at(2*i)<<endl;
      |                             ^
a.cc:13:48: error: expected ';' before ')' token
   13 |                 for(int i=0; i<(str.size())/2+1){
      |                                                ^
      |                                                ;
a.cc:14:29: error: expected primary-expression before '.' token
   14 |                 cout<<string.at(2*i)<<endl;
      |                             ^
Language: C++

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

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

    for (int i = 0; i < s.size(); i++)
    {
        if (i % 2 == 0)
        {
            cout << s[i];
        }
    }
    cout << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:27: error: request for member 'size' in 's', which is of non-class type 'int'
    9 |     for (int i = 0; i < s.size(); i++)
      |                           ^~~~
a.cc:13:22: error: invalid types 'int[int]' for array subscript
   13 |             cout << s[i];
      |                      ^
Language: C++

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

int main() {
    string s;
    cin >> s;
    for (int i=0; i<s.size(); i++) {
        if (i % 2 == 0) {
            cout << s.at(i);
        } else {
            continue;
        }
    }
    endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:9: error: statement cannot resolve address of overloaded function
   14 |     endl;
      |         ^
Language: C++

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

int main(){

  string S;
  getline(cin, S);

  for(int i=0; i<S.size(); i++){
    if(!(i%2) cout << S[i] << flush;
  }

  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:14: error: expected ';' before 'cout'
   11 |     if(!(i%2) cout << S[i] << flush;
      |              ^~~~~
      |              ;
a.cc:12:3: error: expected primary-expression before '}' token
   12 |   }
      |   ^
a.cc:11:37: error: expected ')' before '}' token
   11 |     if(!(i%2) cout << S[i] << flush;
      |       ~                             ^
      |                                     )
   12 |   }
      |   ~                                  
a.cc:12:3: error: expected primary-expression before '}' token
   12 |   }
      |   ^
Language: C

#include <bits/stdc++.h>

using namespace std;

int main(int argc, char const *argv[])
{
	string S;
	cin >> S;
	for (int i = 0; i < S.size(); i += 2){
		cout << S.at(i) << endl;	
	}	
	return 0;
}

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

#include<iostream>
#include<cstring>
using namespace std;
int main()
{
	char str[100001];
	gets(str);
	for(int i=0;i<strlen(str);i+=2){
		cout<<str[i];
	}
	cout<<"\n";
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
    7 |         gets(str);
      |         ^~~~
      |         getw
Language: C++

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

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

  for (int i = 0; i < N; i+=2) {
    cout << s.at(i) << endl;
  }
  cout << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:23: error: 'N' was not declared in this scope
    8 |   for (int i = 0; i < N; i+=2) {
      |                       ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string s,c;cin>>s;
  n=s.size();
  for(int i=1;i<n;i+=2){
    c+=s[i];}
  cout<<c;}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:3: error: 'n' was not declared in this scope
    5 |   n=s.size();
      |   ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main () {
	string s;
	cin >> s;
	int size = (int)s.size();
	int half_size;
	string result = "";
	if(size % 2 == 1){
		half_size = (size - 1)/2;
	}else{
		half_size = size/2;
	}
	for (int i = 0; i < half_size; ++i){

	}
	{
		result.append(s[2 * i]);
	}
	cout << result << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:37: error: 'i' was not declared in this scope
   18 |                 result.append(s[2 * i]);
      |                                     ^
Language: C++

#include<iostream>
#include<string>
#include<vector>
#include<iomanip>
#include<algorithm>
#include<queue>
#include<stack>
#include<map>
using namespace std;
#define ll long long
int main(){
    string s;
    cin >>s;
    for(i=0;i<s.size();i+=2){
      cout << s[i];
    }
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:14:9: error: 'i' was not declared in this scope
   14 |     for(i=0;i<s.size();i+=2){
      |         ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
 
 
 
int main(){
   
    char s;
    cin >> s;
    char a;
    int N = 100010;

    for (int i = 0; i < N; i++){
      if (i % 2 == 0){
        a = a + s[i];
      }
    }

    cout << a << endl;
  }
 

Compiler output:
a.cc: In function 'int main()':
a.cc:16:18: error: invalid types 'char[int]' for array subscript
   16 |         a = a + s[i];
      |                  ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
 
 
 
int main(){
   
    char s;
    cin >> s;
    char a;
    int N = 100010;

    for (int i = 0; i < N; i++){
      if (i % 2 == 0){
        a = a + char s[i];
      }
    }

    cout << a << endl;
  }
 

Compiler output:
a.cc: In function 'int main()':
a.cc:16:17: error: expected primary-expression before 'char'
   16 |         a = a + char s[i];
      |                 ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
 
 
 
int main(){
   
    char s;
    cin >> s;
    char a;
    int N = 100010

    for (int i = 0; i < N; i++){
      if (i % 2 == 0){
        a = a + char s[i];
      }
    }

    cout << a << endl;
  }
 

Compiler output:
a.cc: In function 'int main()':
a.cc:14:5: error: expected ',' or ';' before 'for'
   14 |     for (int i = 0; i < N; i++){
      |     ^~~
a.cc:14:21: error: 'i' was not declared in this scope
   14 |     for (int i = 0; i < N; i++){
      |                     ^
Language: C++

#include<iostream>
#include<cstring>
using namespace std;
int main()
{
	char str[100001];
	int ans=0;
	gets(str);
	for(int i=0;i<strlen(str);i++){
		if(i%2==0) cout<<str[i];
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:9: error: 'gets' was not declared in this scope; did you mean 'getw'?
    8 |         gets(str);
      |         ^~~~
      |         getw
Language: C++

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

int main(){
    string s;
    int N = s.size();
    cin >> s;
    for (int i =0; i<N; i+=2){
                 m += s[i];
     }
    cout << m << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:18: error: 'm' was not declared in this scope
   10 |                  m += s[i];
      |                  ^
a.cc:12:13: error: 'm' was not declared in this scope
   12 |     cout << m << endl;
      |             ^
Language: C++

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

int main(){
    string s,m;
    int N = s.size();
    cin >> s;
    for (int i =0; i<N; i++){
                 m[i]=s[2*i-1]
     }
    cout << m << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:31: error: expected ';' before '}' token
   10 |                  m[i]=s[2*i-1]
      |                               ^
      |                               ;
   11 |      }
      |      ~
Language: C++

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

int main(){
    string s,m;
    cin >> s;
    for (int i =0; i<100000; i++){
                 m[i]=s[2*i-1]
     }
    cout << m << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:31: error: expected ';' before '}' token
    9 |                  m[i]=s[2*i-1]
      |                               ^
      |                               ;
   10 |      }
      |      ~
Language: C++

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <algorithm>
#include <set>
using namespace std;

int main()
{
    string s;
    cin >> s;
    for(i = 0;i < s.size();++i){
        if(i % 2 == 0){
            cout << s.at(i);
        }
    }
    cout << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:9: error: 'i' was not declared in this scope
   14 |     for(i = 0;i < s.size();++i){
      |         ^
Language: C++

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

int main() {
	string s,t;cin>>s;
  	for(int i=0;i<s.size();i++){
    	if(i%2==0) t+=s[i];
    }
  	cout<<t<<endl;
}

Compiler output:
a.cc:1:1: error: 'include' does not name a type
    1 | include <bits/stdc++.h>
      | ^~~~~~~
a.cc: In function 'int main()':
a.cc:5:9: error: 'string' was not declared in this scope
    5 |         string s,t;cin>>s;
      |         ^~~~~~
a.cc:5:20: error: 'cin' was not declared in this scope
    5 |         string s,t;cin>>s;
      |                    ^~~
a.cc:5:25: error: 's' was not declared in this scope
    5 |         string s,t;cin>>s;
      |                         ^
a.cc:7:20: error: 't' was not declared in this scope
    7 |         if(i%2==0) t+=s[i];
      |                    ^
a.cc:9:9: error: 'cout' was not declared in this scope
    9 |         cout<<t<<endl;
      |         ^~~~
a.cc:9:15: error: 't' was not declared in this scope
    9 |         cout<<t<<endl;
      |               ^
a.cc:9:18: error: 'endl' was not declared in this scope
    9 |         cout<<t<<endl;
      |                  ^~~~
Language: C++

#include<iostream> 
#include<vector> 
#include<string> 
#include<algorithm> 
using namespace std; 
int main()
{
	string s;
	cin >> s;
	string a = "";
	for (int i = 0; i < s.size(); i+=2)
	{
		a += s.at(i);
	}
	cout << a << endl;


Compiler output:
a.cc: In function 'int main()':
a.cc:15:27: error: expected '}' at end of input
   15 |         cout << a << endl;
      |                           ^
a.cc:7:1: note: to match this '{'
    7 | {
      | ^
Language: C++

#include <bits/stdc++.h>

using namespace std;

int main(){
	string s;
	cin >> s;
	for(int i=0; i<s.length; i+=2){
		cout << s[i];
	}
	cout << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:26: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::length() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
    8 |         for(int i=0; i<s.length; i+=2){
      |                        ~~^~~~~~
      |                                ()
Language: C

#include<stdio.h>
 
int main(void){
	char s[10002];
	if (scanf_s("%[abcdefghijklmnopqrstuvwxyz]", s) == 1);
	for (int i = 0;; i += 2){
		printf("%c", s[i]);
		if (s[i] == '\0' || s[i + 1] == '\0')
			break;
	}
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:5:13: error: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    5 |         if (scanf_s("%[abcdefghijklmnopqrstuvwxyz]", s) == 1);
      |             ^~~~~~~
      |             scanf
Language: C

#include<stdio.h>

int main(void){
	char s[10002];
	if (scanf_s("%s",&s) == 1);
	for (int i = 0;; i += 2){
		printf("%c", s[i]);
		if (s[i] == '\0' || s[i + 1] == '\0')
			break;
	}
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:5:13: error: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    5 |         if (scanf_s("%s",&s) == 1);
      |             ^~~~~~~
      |             scanf
Language: C

#include<stdio.h>
 
int main(void){
	char s[10002];
	if (scanf("%s",s) == 1);
    for(int i = 0;;i+=2){
      printf("%c",s[i]);
      if (s[i] = '\0' || s[i+1] = '\0')
        break;
    }
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:8:33: error: lvalue required as left operand of assignment
    8 |       if (s[i] = '\0' || s[i+1] = '\0')
      |                                 ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  String S; cin>>S;
  for(int i=0;i<size(S);i+=2)cout<<S[i];
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:3: error: 'String' was not declared in this scope
    4 |   String S; cin>>S;
      |   ^~~~~~
a.cc:4:18: error: 'S' was not declared in this scope
    4 |   String S; cin>>S;
      |                  ^
Language: C++

#include <bits/stdc++.h>
#define For(i, begin, end) for(int i=begin;i<end;i++)
#define Rep(i, n) For(i,0,n)
#define Sort(v) sort(v.begin(),v.end())
using namespace std;

int main(){
  string S;cin>>S;
  REP(i,(S.size()+1)/2)cout<<S[2*i];
  
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:7: error: 'i' was not declared in this scope
    9 |   REP(i,(S.size()+1)/2)cout<<S[2*i];
      |       ^
a.cc:9:3: error: 'REP' was not declared in this scope; did you mean 'Rep'?
    9 |   REP(i,(S.size()+1)/2)cout<<S[2*i];
      |   ^~~
      |   Rep
Language: C++

#include<iostream>
#include<cstdio>
using namespace std;
int main()
{ char a[100000];
 int j;
while(cin>>a)
{

    for(j=0;j<strlen(a);j+=2)
 cout<<a[j];
       cout<<endl;
}

return 0;}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:15: error: 'strlen' was not declared in this scope
   10 |     for(j=0;j<strlen(a);j+=2)
      |               ^~~~~~
a.cc:3:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    2 | #include<cstdio>
  +++ |+#include <cstring>
    3 | using namespace std;
Language: Java

#include <bits/stdc++.h>
using namespace std;
int main(){
    string s;
    cin >> s;
    for(int i = 0; i < s.size(); i += 2) cout << s.at(i);
}


Compiler output:
Main.java:1: error: illegal character: '#'
#include <bits/stdc++.h>
^
Main.java:1: error: class, interface, enum, or record expected
#include <bits/stdc++.h>
         ^
Main.java:5: error: not a statement
    cin >> s;
        ^
Main.java:6: error: not a statement
    for(int i = 0; i < s.size(); i += 2) cout << s.at(i);
                                              ^
Main.java:3: error: unnamed classes are a preview feature and are disabled by default.
int main(){
^
  (use --enable-preview to enable unnamed classes)
5 errors
Language: C++

#include<bits/stdc++.h>
#include<string>
using namespace std;
int main(){
  string s;
  string u;
  int t = s.size();
  for(int i = 0; 2*i + 1 <= t; i += 2){
     u += s[i]
  }
  cout << u << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:15: error: expected ';' before '}' token
    9 |      u += s[i]
      |               ^
      |               ;
   10 |   }
      |   ~
Language: C++

#include<bits/stdc++.h>
#include<string>
using namespace std;
int main(){
  string s;
  string u = '';
  int t = s.size();
  for(int i = 0; 2*i + 1 <= t; i++){
     u = u + s[2*i + 1];
  }
  cout << u << endl;
}

Compiler output:
a.cc:6:14: error: empty character constant
    6 |   string u = '';
      |              ^~
a.cc: In function 'int main()':
a.cc:6:14: error: conversion from 'char' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
Language: Java

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int s = sc.nextInt();
        int result = 0;
        int[] p = new int[s];
        int pl = 2;
        int res;
        
        for(int i = 0; i < s; i++){

        	res = p[i];
        	i++;
        	} 
        result = res;
        System.out.println(result);
    }
}

Compiler output:
Main.java:16: error: variable res might not have been initialized
        result = res;
                 ^
1 error
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  string s;
  cin>>s;
  string ans;
  l = s.size();
  for(int i=0;i<l;i += 2){
    ans += s.at(i);
  }
  cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:3: error: 'l' was not declared in this scope
    8 |   l = s.size();
      |   ^
Language: C++

//
//  main.cpp
//  
//
//  Created by 小泉孝弥 on 2018/10/11.
//

#include <stdio.h>
#include <iostream>
#include <string>
#include <Algorithm>
using namespace std;
int main(){
    string S;
    cin >> S;
    string oddS = "";
    int len = S.size();
    for(int i = 0; i < len; i = i + 2){
        oddS += S[i];
    }
    cout << oddS << endl;
    return 0;
}


Compiler output:
a.cc:11:10: fatal error: Algorithm: No such file or directory
   11 | #include <Algorithm>
      |          ^~~~~~~~~~~
compilation terminated.
Language: C++

s = gets.chomp
answer = ""
S.length.times{
    if i % 2 != 0
        answer += s[i]
}
puts answer

Compiler output:
a.cc:1:1: error: 's' does not name a type
    1 | s = gets.chomp
      | ^
a.cc:7:1: error: 'puts' does not name a type
    7 | puts answer
      | ^~~~
Language: Java

import java.util.*;
public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		for(int i=0; i<n; i+=2){
			System.out.print(s.charAt(i));
		}
		System.out.println("");
	}
}

Compiler output:
Main.java:6: error: cannot find symbol
		for(int i=0; i<n; i+=2){
		               ^
  symbol:   variable n
  location: class Main
1 error
Language: C++

#include <cstring>
 
using namespace std;
 
int main()
{   
    int i,j;
    char str[100001];
    cin >> str;
    j = strlen(str);
    for(i=0;i<j;i+=2){
    cout << str[i];
  }
       return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:5: error: 'cin' was not declared in this scope
    9 |     cin >> str;
      |     ^~~
a.cc:2:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    1 | #include <cstring>
  +++ |+#include <iostream>
    2 | 
a.cc:12:5: error: 'cout' was not declared in this scope
   12 |     cout << str[i];
      |     ^~~~
a.cc:12:5: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: C++

#include<iostream>
#include <string>
 
using namespace std;
 
int main()
{   
    int i,j;
    char str[100001];
    cin >> str;
    j = strlen(str);
    for(i=0;i<j;i+=2){
    cout << str[i];
  }
       return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:9: error: 'strlen' was not declared in this scope
   11 |     j = strlen(str);
      |         ^~~~~~
a.cc:2:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    1 | #include<iostream>
  +++ |+#include <cstring>
    2 | #include <string>
Language: C++

#include <iostream>
#include <algorithm>
#include <cmath>
#include <string>
#include <array>
#include <vector>
#include <functional>
#include <unordered_map>
#include <map>
#include <numeric>
#include <limits>
#include <utility>
#include <queue>
#include <random>
using namespace std;

int main(){
	char s[100];

	cin >> s;

	int x,i;

	x = strlen(s);
	
	for (i = 0; i < x; i++) {
		if (i < (x + 1) / 2) {
			s[i] = s[i * 2];
		} else {
			s[i] = ' ';
		}
	}

	cout << s;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:13: error: 'strlen' was not declared in this scope
   24 |         x = strlen(s);
      |             ^~~~~~
a.cc:15:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
   14 | #include <random>
  +++ |+#include <cstring>
   15 | using namespace std;