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

#include <bits/stdc++.h>
#define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)

int main(){
    string s;
    std::cin>>s;
    int a=0x61;
    sort(s.begin(),s.end());
    rep(i,0,s.length()){if(s[i]==a)a++;else break;}
    std::cout<<char(a);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:5: error: 'string' was not declared in this scope
    5 |     string s;
      |     ^~~~~~
a.cc:5:5: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 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/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:6:15: error: 's' was not declared in this scope
    6 |     std::cin>>s;
      |               ^
a.cc:8:5: error: 'sort' was not declared in this scope; did you mean 'std::sort'?
    8 |     sort(s.begin(),s.end());
      |     ^~~~
      |     std::sort
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note: 'std::sort' declared here
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
a.cc:2:24: error: 'll' was not declared in this scope
    2 | #define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)
      |                        ^~
a.cc:9:5: note: in expansion of macro 'rep'
    9 |     rep(i,0,s.length()){if(s[i]==a)a++;else break;}
      |     ^~~
a.cc:9:9: error: 'i' was not declared in this scope
    9 |     rep(i,0,s.length()){if(s[i]==a)a++;else break;}
      |         ^
a.cc:2:35: note: in definition of macro 'rep'
    2 | #define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)
      |                                   ^
Language: C++

#include <bits/stdc++.h>
#define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)

int main(){
    string s;
    cin>>s;
    int a=0x61;
    sort(s.begin(),s.end());
    rep(i,0,s.length()){if(s[i]==a)a++;else break;}
    cout<<char(a);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:5: error: 'string' was not declared in this scope
    5 |     string s;
      |     ^~~~~~
a.cc:5:5: note: suggested alternatives:
In file included from /usr/include/c++/14/string:41,
                 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/stringfwd.h:77:33: note:   'std::string'
   77 |   typedef basic_string<char>    string;
      |                                 ^~~~~~
/usr/include/c++/14/string:76:11: note:   'std::pmr::string'
   76 |     using string    = basic_string<char>;
      |           ^~~~~~
a.cc:6:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |     cin>>s;
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:6:10: error: 's' was not declared in this scope
    6 |     cin>>s;
      |          ^
a.cc:8:5: error: 'sort' was not declared in this scope; did you mean 'std::sort'?
    8 |     sort(s.begin(),s.end());
      |     ^~~~
      |     std::sort
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note: 'std::sort' declared here
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
a.cc:2:24: error: 'll' was not declared in this scope
    2 | #define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)
      |                        ^~
a.cc:9:5: note: in expansion of macro 'rep'
    9 |     rep(i,0,s.length()){if(s[i]==a)a++;else break;}
      |     ^~~
a.cc:9:9: error: 'i' was not declared in this scope
    9 |     rep(i,0,s.length()){if(s[i]==a)a++;else break;}
      |         ^
a.cc:2:35: note: in definition of macro 'rep'
    2 | #define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)
      |                                   ^
a.cc:10:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |     cout<<char(a);
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <utility>
#include <tuple>
#include <string>
#include <cctype>
#include <cstdio>
#include <math.h>
using f32 = float;
using f64 = double;
using f80 = __float80;
using namespace std;
using LL = long long;
using ULL = unsigned long long;
using vi = vector<int>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvi = vector<vi>;
using vs = vector<string>;
using vl = vector<LL>;
using vvl = vector<vl>;
using P = pair<int, int>;
using T = tuple<int, int, int>;
using vp = vector<P>;
#define REP(i, n) for (LL i = 0; i < (int)(n); i++)
#define FOR(i, m, n) for (LL i = m; i < n; i++)
#define SORT(x) sort(x.begin(), x.end())
#define REVE(x) reverse(x.begin(), x.end())
#define all(x) (x).begin(), (x).end()
#define fst first
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pob pop_back
#define sw swap
#define UP(x) transform(x.begin(), x.end(), x.begin(), ::toupper);
#define LOW(x) transform(x.begin(), x.end(), x.begin(), ::tolower);
struct initon
{
    initon()
    {
        cin.tie(0);
        ios::sync_with_stdio(false);
    };
};
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return 1;
    }
    return 0;
}
int main()
{
    LL n,a,b,c;
    string A;
    cin >> A;
     vector<LL> aa(A.size());
   for(char c='a';c<='z';c++){
       if(A.find(c)==string::npos){
			cout<<c<<endl;
			return 0;
		}
	}
	cout<<"None"<<endl;
	return 0;
}
   
}

Compiler output:
a.cc:85:1: error: expected declaration before '}' token
   85 | }
      | ^
Language: C++

//
//  main.cpp
//  AC
//
//  Created by makinofuya on 2019/07/08.
//  Copyright © 2019 makinofuya. All rights reserved.
//
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <stack>
#include <math.h>

typedef long long ll;
using namespace std;
#define mod 1000000007
#define rep(i,n) for(ll i=0;i<n;i++)
#define out(s) cout << s << endl


int main(){
    string s;cin >> s;
    sort(s.begin(),s.end());
    bool a[26];
    for(int i=0;i<26;i++){
        a[i]=false;
    }
    for(int i=0;i<s.size();i++){
        a[s[i]-'a']=true;
    }
    
    for(int i=0;i<26;i++){
        if(a[i]==false){
            cout << char('a'+i) << endl;
            return 0;
        }
    }
    cout << "None" << endl;
    return 0;
}
//
//  main.cpp
//  AC
//
//  Created by makinofuya on 2019/07/08.
//  Copyright © 2019 makinofuya. All rights reserved.
//
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <stack>
#include <math.h>

typedef long long ll;
using namespace std;
#define mod 1000000007
#define rep(i,n) for(ll i=0;i<n;i++)
#define out(s) cout << s << endl


int main(){
    string s;cin >> s;
    sort(s.begin(),s.end());
    bool a[26];
    for(int i=0;i<26;i++){
        a[i]=false;
    }
    for(int i=0;i<s.size();i++){
        a[s[i]-'a']=true;
    }
    
    for(int i=0;i<26;i++){
        if(a[i]==false){
            cout << char('a'+i) << endl;
            return 0;
        }
    }
    cout << "None" << endl;
    return 0;
}


Compiler output:
a.cc:63:5: error: redefinition of 'int main()'
   63 | int main(){
      |     ^~~~
a.cc:22:5: note: 'int main()' previously defined here
   22 | int main(){
      |     ^~~~
Language: C++

#incldue <iostream>
#include <vector>

using namespace std;

int main(){
  string s;
  cin >> s;
  vector<bool> al(24,false);
  
  for(int i = 0; i < s.size(); i++){
    al[s[i] - 'a'] = true;
  }
  
  bool exsisted = false;
  char ans;
  for(int i = 0; i < 24; i++){
    if(!al[i]){
      ans = i + 'a';
      exsisted = true;
      break;
    }
  }
  if(!exsisted) cout << "None";
  else cout << ans;
}

Compiler output:
a.cc:1:2: error: invalid preprocessing directive #incldue; did you mean #include?
    1 | #incldue <iostream>
      |  ^~~~~~~
      |  include
a.cc: In function 'int main()':
a.cc:7:3: error: 'string' was not declared in this scope
    7 |   string s;
      |   ^~~~~~
a.cc:3:1: note: 'std::string' is defined in header '<string>'; this is probably fixable by adding '#include <string>'
    2 | #include <vector>
  +++ |+#include <string>
    3 | 
a.cc:8:3: error: 'cin' was not declared in this scope
    8 |   cin >> s;
      |   ^~~
a.cc:3:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    2 | #include <vector>
  +++ |+#include <iostream>
    3 | 
a.cc:8:10: error: 's' was not declared in this scope
    8 |   cin >> s;
      |          ^
a.cc:24:17: error: 'cout' was not declared in this scope
   24 |   if(!exsisted) cout << "None";
      |                 ^~~~
a.cc:24:17: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:25:8: error: 'cout' was not declared in this scope
   25 |   else cout << ans;
      |        ^~~~
a.cc:25:8: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<(int)(n);i++)
#define fs first
#define sc second
typedef pair<ll, ll> l_l;
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))

int main(){
  string s;
  cin>>s;
  vector<int> a(26);
  rep(i,s.size)a.at(s.at(i)-'a')++;
  rep(i,26){
    if(a.at(i)==0)cout<<(char)i+'a'<<endl;
    return 0;}
  cout<<"None"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:11: error: invalid use of member function 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size() const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]' (did you forget the '()' ?)
   17 |   rep(i,s.size)a.at(s.at(i)-'a')++;
      |           ^
a.cc:4:38: note: in definition of macro 'rep'
    4 | #define rep(i,n) for(int i=0;i<(int)(n);i++)
      |                                      ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<(int)(n);i++)
#define fs first
#define sc second
typedef pair<ll, ll> l_l;
#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))

int main(){
  string s;
  cin>>s;
  set<char>a;
  rep(i,s.size())a.insert(s[i]);
  if(a.size()==26)cout<<"None"<<endl;
  else {char ans='z';
    rep(i,a.size()){
    if(ans>a[i])ans=a[i];}
  cout<<ans<<endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:13: error: no match for 'operator[]' (operand types are 'std::set<char>' and 'int')
   21 |     if(ans>a[i])ans=a[i];}
      |             ^
a.cc:21:22: error: no match for 'operator[]' (operand types are 'std::set<char>' and 'int')
   21 |     if(ans>a[i])ans=a[i];}
      |                      ^
Language: C++

#include <iostream>
#include <string>
#include <map>

using namespace std;

int main() {
    char str[100000];
    cin >> str;

    // cout << str.length() << endl;

    map<char, int> mp;
    char i;
    for(i='a'; i<='z'; i++) {
        mp[i] = 0;
    }

    int j;
    
    for(j=0; j<strlen(str); j++) {
        mp[str[j]] += 1;
    }

    // cout << mp['a'] << endl;

    int flag=0;

    for(i='a'; i<='z'; i++) {
        if(mp[i]==0) {
            flag = 1;
            break;
        }
    }

    if(flag) cout << i << endl;
    else cout << "None" << endl;

    return 0;
    
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:16: error: 'strlen' was not declared in this scope
   21 |     for(j=0; j<strlen(str); j++) {
      |                ^~~~~~
a.cc:4:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    3 | #include <map>
  +++ |+#include <cstring>
    4 |
Language: C++

#include <iostrem>

using namespace std;

int main() {
  string in = "";
  cin >> in;
  bool check[26];
  for (int i=0; i<26; i++) check[i] = false;
  for (char c : in) check[c-'a'] = true;
  for (int i=0; i<26; i++) {
    if (!check[i]) {
      cout << 'a' + i << endl;
      return 0;
    }
  }
  cout << 'None' << endl;
  return 0;
}


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

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

int main() {
  string s;
  cin >> s;
  int a = 0;
  char b = '1';
  string sample = "abcdefghijklmnopqrstuvwxyz";
  sort(s.begin(),s.end());
  for(int i = 0; i < s.size(); i++){
    if(s.at(i) == b){
      continue;
    }else{
      if(s.at(i) != sample.at(a)){
        break;
      }else{
        if(s.at(i) == 'z'){
          a++
          break;
        }
        a++;
        b = s.at(i);
      }
    }
  }
  if(a != 27)
    cout << sample.at(a) << endl;
  else
    cout << "None" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:14: error: expected ';' before 'break'
   19 |           a++
      |              ^
      |              ;
   20 |           break;
      |           ~~~~~
Language: C++

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

int main() {
  string s;
  cin >> s;
  int a = 0;
  char b = '1';
  string sample = "abcdefghijklmnopqrstuvwxyz";
  sort(s.begin(),s.end());
  for(int i = 0; i < s.size(); i++){
    if(s.at(i) == b){
      continue;
    }else{
      if(s.at(i) != sample(a)){
        break;
      }else{
        if(s.at(i) == 'z')
          break;
        a++;
        b = s.at(i);
      }
    }
  }
  cout << sample(a) << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:27: error: no match for call to '(std::string {aka std::__cxx11::basic_string<char>}) (int&)'
   15 |       if(s.at(i) != sample(a)){
      |                     ~~~~~~^~~
a.cc:25:17: error: no match for call to '(std::string {aka std::__cxx11::basic_string<char>}) (int&)'
   25 |   cout << sample(a) << endl;
      |           ~~~~~~^~~
Language: C++

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

int main() {
  string s;
  cin >> s;
  int a = 0;
  char b = '1';
  string sample = abcdefghijklmnopqrstuvwxyz;
  sort(s.begin(),s.end());
  for(int i = 0; i < s.size(); i++){
    if(s.at(i) == b){
      continue;
    }else{
      if(s.at(i) != sample(a)){
        break;
      }else{
        if(s.at(i) == 'z')
          break;
        a++;
        b = s.at(i);
      }
    }
  }
  cout << sample(a) << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:19: error: 'abcdefghijklmnopqrstuvwxyz' was not declared in this scope
    9 |   string sample = abcdefghijklmnopqrstuvwxyz;
      |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:15:27: error: no match for call to '(std::string {aka std::__cxx11::basic_string<char>}) (int&)'
   15 |       if(s.at(i) != sample(a)){
      |                     ~~~~~~^~~
a.cc:25:17: error: no match for call to '(std::string {aka std::__cxx11::basic_string<char>}) (int&)'
   25 |   cout << sample(a) << endl;
      |           ~~~~~~^~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
 
int main(){
string a;
  char b='a';
  int *c=1;
  cin>>a;
  sort(a.begin(),a.end());
  a.erase(unique(a.begin(), a.end()), a.end());
  if(a.size()==26)
    cout<<"None"<<endl;
  for(int i=0;i<a.size();i++){
    if(a.at(i)!=b){
      cout<<b<<endl;
      break;
    }
    b=b+1;
  }
}
    


Compiler output:
a.cc: In function 'int main()':
a.cc:7:10: error: invalid conversion from 'int' to 'int*' [-fpermissive]
    7 |   int *c=1;
      |          ^
      |          |
      |          int
Language: C++

#include<bits/stdc++.h>
using namespace std;
 
int main(){
string a;
  char b='a';
  int *c;
  cin>>a;
  sort(a.begin(),a.end());
  a.erase(unique(a.begin(), a.end()), a.end());
  if(a.size()==26)
    cout<<"None"<<endl;
  for(int i=0;i<a.size();i++){
    if(a.at(i)!=b){
      cout<<b<<endl;
      break;
    }
    c=&b;
    c++;
    b=c;
  }
}
    


Compiler output:
a.cc: In function 'int main()':
a.cc:18:7: error: cannot convert 'char*' to 'int*' in assignment
   18 |     c=&b;
      |       ^~
      |       |
      |       char*
a.cc:20:7: error: invalid conversion from 'int*' to 'char' [-fpermissive]
   20 |     b=c;
      |       ^
      |       |
      |       int*
Language: C++

#include<bits/stdc++.h>
using namespace std;
 
int main(){
string a;
  char b='a';
  int c;
  cin>>a;
  sort(a.begin(),a.end());
  a.erase(unique(a.begin(), a.end()), a.end());
  if(a.size()==26)
    cout<<"None"<<endl;
  for(int i=0;i<a.size();i++){
    if(a.at(i)!=b){
      cout<<b<<endl;
      break;
    }
    *c=&b;
    c++;
    b=c;
  }
}
    


Compiler output:
a.cc: In function 'int main()':
a.cc:18:5: error: invalid type argument of unary '*' (have 'int')
   18 |     *c=&b;
      |     ^~
Language: C++

#include<bits/stdc++.h>
using namespace std;
 
int main(){
string a;
  char b='a';
  int c;
  cin>>a;
  sort(a.begin(),a.end());
  a.erase(unique(a.begin(), a.end()), a.end());
  if(a.size()==26)
    cout<<"None"<<endl;
  for(int i=0;i<a.size();i++){
    if(a.at(i)!=b){
      cout<<b<<endl;
      break;
    }
    c=&b;
    c++;
    b=c;
  }
}
    


Compiler output:
a.cc: In function 'int main()':
a.cc:18:7: error: invalid conversion from 'char*' to 'int' [-fpermissive]
   18 |     c=&b;
      |       ^~
      |       |
      |       char*
Language: C++

#include<bits/stdc++.h>
using namespace std;
 
int main(){
string a;
  char b='a';
  cin>>a;
  sort(a.begin(),a.end());
  a.erase(unique(a.begin(), a.end()), a.end());
  if(a.size()==26)
    cout<<"None"<<endl;
  for(int i=0;i<a.size();i++){
    if(a.at(i)!=b){
      cout<<b<<endl;
      break;
    }
    b=b+*1;
  }
}
    

Compiler output:
a.cc: In function 'int main()':
a.cc:17:9: error: invalid type argument of unary '*' (have 'int')
   17 |     b=b+*1;
      |         ^~
Language: C++

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

int main(){
    string s;
    cin>>s;
    sort(s.begin(),s.end());
    int ia='a';
    for(int i=0;i<s.size();i++){
        if(s[i]==ia) ia++;
    }
    cout<<(ia=='z'+1?"None":(char)ia)<<endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:12:21: error: operands to '?:' have different types 'const char*' and 'char'
   12 |     cout<<(ia=='z'+1?"None":(char)ia)<<endl;
      |            ~~~~~~~~~^~~~~~~~~~~~~~~~
Language: C++

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

int main(){
    string s;
    cin>>s;
    sort(s.begin(),s,end());
    int ia='a';
    for(int i=0;i<s.size();i++){
        if(s[i]==ia) ia++;
    }
    cout<<(ia=='z'+1?"None":(char)ia)<<endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:25: error: no matching function for call to 'end()'
    7 |     sort(s.begin(),s,end());
      |                      ~~~^~
In file included from /usr/include/c++/14/bits/algorithmfwd.h:39,
                 from /usr/include/c++/14/bits/stl_algo.h:59,
                 from /usr/include/c++/14/algorithm:61,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/initializer_list:99:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/range_access.h:74:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:85:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:106:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:   candidate expects 1 argument, 0 provided
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/valarray:1249:5: note: candidate: 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
 1249 |     end(valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1249:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/valarray:1265:5: note: candidate: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
 1265 |     end(const valarray<_Tp>& __va) noexcept
      |     ^~~
/usr/include/c++/14/valarray:1265:5: note:   candidate expects 1 argument, 0 provided
a.cc:12:21: error: operands to '?:' have different types 'const char*' and 'char'
   12 |     cout<<(ia=='z'+1?"None":(char)ia)<<endl;
      |            ~~~~~~~~~^~~~~~~~~~~~~~~~
Language: C++

#include <cstdio>
 
char S[101010];
 
int main()
{
	scanf("%s", S);
 
	bool app[26];
	for (int i = 0; i < 26; ++i) {
		app[i] = false;
	}
	for (int i = 0; S[i] != '\0'; ++i) {
		app[S[i] - 'a'] = true;
	}
	for (int i = 0; i < 26; ++i) {
		if (!app[i]) {
			printf("%c\n", (char)(i + 'a'));
			return 0;
		}
	}
	puts("None");
	return 0;
}
#include <cstdio>

char S[101010];

int main()
{
	scanf("%s", S);

	bool app[26];
	for (int i = 0; i < 26; ++i) {
		app[i] = false;
	}
	for (int i = 0; S[i] != '\0'; ++i) {
		app[S[i] - 'a'] = true;
	}
	for (int i = 0; i < 26; ++i) {
		if (!app[i]) {
			printf("%c\n", (char)(i + 'a'));
			return 0;
		}
	}
	puts("None");
	return 0;
}


Compiler output:
a.cc:27:6: error: redefinition of 'char S [101010]'
   27 | char S[101010];
      |      ^
a.cc:3:6: note: 'char S [101010]' previously declared here
    3 | char S[101010];
      |      ^
a.cc:29:5: error: redefinition of 'int main()'
   29 | int main()
      |     ^~~~
a.cc:5:5: note: 'int main()' previously defined here
    5 | int main()
      |     ^~~~
Language: C

#include <stdio.h>
#include <string.h>
int main(){
  int i;
  char s[100001];
  scanf("%s",s);
  for(i='a';i<='z';i++)if(strchr(s,i)==0)break;
  if(i>z)puts("None");
  else printf("%c",i);
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:8:8: error: 'z' undeclared (first use in this function)
    8 |   if(i>z)puts("None");
      |        ^
main.c:8:8: 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;
  set<char> st;
  for (int i=0; i<s.length; i++){
    st.insert(s.at(i));
  }
  for (int i=0; i<26; i++){
    if (st.count('a'+i) == 0) {
      cout << (char)('a'+i) << endl;
      return 0;
    }
  }
  cout << "None" << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:21: 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++){
      |                   ~~^~~~~~
      |                           ()
Language: C++

#include <bits/stdc++.h>
#define all(x) begin(x), end(x)
#define dbg(x) cerr << #x << " = " << x << endl
#define _ << ' ' <<
using namespace std;
using ll = long long;
using vi = vector<int>;


int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    for (char c = 'a'; c <= 'z'; ++c)
        if (find(all(s), c) != s.end())
            return cout << c, 0;
    cout << "None";
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:22: error: 's' was not declared in this scope
   15 |         if (find(all(s), c) != s.end())
      |                      ^
a.cc:2:22: note: in definition of macro 'all'
    2 | #define all(x) begin(x), end(x)
      |                      ^
Language: C++

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

int main() {
  string S;
  cin >> S;
  bool B[26];
  bool c = ture;
  for (int i = 0; i < 26; i++) {
    B[i] = false;
  }
  for (int i = 0; i < S.size(); i++) {
    B[S[i] - 'a'] = true;
  }
  for (int i = 0; i < 26; i++) {
    if (B[i]) {
      continue;
    }
    else {
      cout << (char)('a' + i) << endl;
      c = false;
      break;
    }
  }
  if (c) {
    cout << "None" << endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:12: error: 'ture' was not declared in this scope
    8 |   bool c = ture;
      |            ^~~~
Language: C++

#include <iostream>
using namespace std ;
int main()
{
	int i;
	char s[100001];
	cin >> s;

	int app[26] = {}; /zenbu0
	
	for (i=0; s[i] != '\0'; i++){
		app[s[i] - 'a'] = 1;
	}
	for (int i = 0; i < 26; ++i) {
		if (!app[i]) {
			printf("%c\n", (char)(i + 'a'));
			return 0;
		}
	}
	cout << "None";
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:27: error: expected primary-expression before '/' token
    9 |         int app[26] = {}; /zenbu0
      |                           ^
a.cc:9:28: error: 'zenbu0' was not declared in this scope
    9 |         int app[26] = {}; /zenbu0
      |                            ^~~~~~
a.cc:11:36: error: expected ';' before ')' token
   11 |         for (i=0; s[i] != '\0'; i++){
      |                                    ^
      |                                    ;
Language: C++

#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <map>
#include <string>
#include <cmath>
#include <set>

#define mod 1000000007

using namespace std;
 
int main(void){

	string s;
	
	cin >> s;
	
	for(int i=0; i<=25; i++){
		if(s.count('a'+i) == 0){
			cout << char('a'+i);
			return 0;
		}
	}
	
	cout << "None";
	
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:20:22: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'count'
   20 |                 if(s.count('a'+i) == 0){
      |                      ^~~~~
Language: C++

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

int main() {
  string S;
  cin>>S;
  for(char c='a'; c<='Z'; c++) {
    if(S.find(c)==S.nops) {
      cout<<c;
      return 0;
    }
  }  
  cout<<"None";
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:21: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'nops'; did you mean 'npos'?
   10 |     if(S.find(c)==S.nops) {
      |                     ^~~~
      |                     npos
Language: C++

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

int main() {
  string S;
  cin>>S;
  for(char c='a'; c<='Z'; c++) {
    if(S.find(c)==S.nops) {
      cout<<c;
      return 0;
    }
  }  
  cout<<"None";
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:21: error: 'std::string' {aka 'class std::__cxx11::basic_string<char>'} has no member named 'nops'; did you mean 'npos'?
    8 |     if(S.find(c)==S.nops) {
      |                     ^~~~
      |                     npos
Language: C++

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

int main(){
  string S;
  cin>>S;
  
  char a,b,c,d,e,f,g,h,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z;
  
  vector<char> ans={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z};
  vector<int>  ans2(26);
  
  for(int i=0;i<S.size();i++){
    
    for(int j=0;j<26;j++){
    if(S.at(i)==ans.at(j)){
      ans2.at(j)++;
    }
    }
  }
  
  for(int i=0;i<26;i++){
    if(ans2.at(i)>0){
      cout<<ans.at(i)<<endl;
      break;
    }
  }
}

      
    

Compiler output:
a.cc: In function 'int main()':
a.cc:10:37: error: 'i' was not declared in this scope
   10 |   vector<char> ans={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z};
      |                                     ^
a.cc:10:72: error: could not convert '{a, b, c, d, e, f, g, h, <expression error>, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z}' from '<brace-enclosed initializer list>' to 'std::vector<char>'
   10 |   vector<char> ans={a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z};
      |                                                                        ^
      |                                                                        |
      |                                                                        <brace-enclosed initializer list>
Language: C++

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

int main(){
  string S;
  string model = "abcdefghijklmnopqrstuvwxyz";
  vector<bool> s(26)=false;
  int d = 0;
  
  cin >> S;
  
  for(int i = 0; i < S.size(); i++){
    if(d == 26)break; 
    for(int j = 0; j < model.size(); j++){
      if(s.at(j))continue;
      if(S.at(i) == model.at(j)){
        s.at(j) = true;
        d++;
        break;
      }
    }
  }
  
  if(d == 26){
    cout << "None" << endl;
  }else{
    for(int i = 0; i < s.size(); i++){
      cout << model.at(i);
    }
    cout << endl;
  }
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:21: error: expected ',' or ';' before '=' token
    7 |   vector<bool> s(26)=false;
      |                     ^
Language: C++

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

template <class T> using V = vector<T>;

using ll = long long;
using db = double;
using st = string;
using ch = char;
using vll = V<ll>;
using vpll =V<pair<ll,ll>>;
using vst = V<st>;
using vdb = V<db>;
using vch = V<ch>;


#define FOR(i,a,b) for(ll i=(a);i<(ll)(b);i++)
#define rFOR(i,a,b) for(ll i=(b);i>(ll)(a);i--)
#define oFOR(i,a,b) for(ll i=(a);i<(ll)(b);i+=2)
#define bgn begin()
#define en end()
#define SORT(a) sort((a).bgn,(a).en)
#define REV(a) reverse((a).bgn,(a).en)
#define M(a,b) max(a,b)
#define rM(a,b) min(a,b)
#define fi first
#define se second
#define sz size()
#define gcd(a,b) __gcd(a,b)
#define co(a) cout<<a<<endl;
#define ci(a) cin>>a;


ll sum(ll n) {
  ll m=0;
  FOR(i,0,20){
    m+=n%10;
    n/=10;
    if(n==0){
      break;
    }
  }
  return m;
}


ll combi(ll n,ll m) {
  ll ans=1;
  rFOR(i,n,n-m){
    ans*=i;
  }
  FOR(i,1,m+1){
    ans/=i;
  }
  return ans;
}


ll lcm(ll a,ll b){
  ll n;
  n=a/gcd(a,b)*b;
  return n;
}


/****************************************\
| Thank you for viewing my code:)        |
| Written by RedSpica a.k.a. RanseMirage |
| Twitter:@asakaakasaka                  | 
\****************************************/


signed main() {
  st s;
  	ci(s);
  ll S=s.sz;
  vch A(S);
  bool b=true;
  FOR(i,0,S){
    A[i]=s[i];
  }
  
  FOR(i,0,26){
    FOR(j,0,s){
    ll a=A[j]-'a'-i;
      if(a!=0){
        co(A[j])
          b=false;
          break;
      }
    }
  }
  if(b){
    co("None")
    }

Compiler output:
a.cc: In function 'int main()':
a.cc:18:35: error: invalid cast from type 'st' {aka 'std::__cxx11::basic_string<char>'} to type 'll' {aka 'long long int'}
   18 | #define FOR(i,a,b) for(ll i=(a);i<(ll)(b);i++)
      |                                   ^~~~~~~
a.cc:85:5: note: in expansion of macro 'FOR'
   85 |     FOR(j,0,s){
      |     ^~~
a.cc:96:6: error: expected '}' at end of input
   96 |     }
      |      ^
a.cc:74:15: note: to match this '{'
   74 | signed main() {
      |               ^
Language: Java

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        String ans = "None";
        char tmp='a';
        for(int i = 0; i < 26; i++) {
            String strTmp = String.valueOf(tmp);
            if (!s.contains(strTmp)) {
            	ans=strTmp;
            	break;
            }
            tmp++;
        }
        System.out.println(ans);
    }
}

Compiler output:
Main.java:3: error: cannot find symbol
        Scanner sc = new Scanner(System.in);
        ^
  symbol:   class Scanner
  location: class Main
Main.java:3: error: cannot find symbol
        Scanner sc = new Scanner(System.in);
                         ^
  symbol:   class Scanner
  location: class Main
2 errors
Language: Java

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        HashSet<String> set = new HashSet<>();

        String ans = "None";

        for(int i = 0; i < s.length(); i++) {
            String tmp =  String.valueOf(s.charAt(i));
            if(set.size() == 26) {
            System.out.println(ans);
            }else {
            	
            for(int j = 0; j < 26; j++) {
                if(s.contains(tmp)) {
                    continue;
                }
                ans=tmp;
                System.out.println(ans);
                break;
            }
            }    
        }
    }
}

Compiler output:
Main.java:3: error: cannot find symbol
        Scanner sc = new Scanner(System.in);
        ^
  symbol:   class Scanner
  location: class Main
Main.java:3: error: cannot find symbol
        Scanner sc = new Scanner(System.in);
                         ^
  symbol:   class Scanner
  location: class Main
Main.java:5: error: cannot find symbol
        HashSet<String> set = new HashSet<>();
        ^
  symbol:   class HashSet
  location: class Main
Main.java:5: error: cannot find symbol
        HashSet<String> set = new HashSet<>();
                                  ^
  symbol:   class HashSet
  location: class Main
4 errors
Language: Java

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.nextLine();
		HashSet<String> set = new HashSet<>();

		String ans = "none";

		for(int i = 0; i < s.length(); i++) {
			set.add(String.valueOf(s.charAt(i)));
			if(set.size() == 26) {
			System.out.println(ans);
			}else {
			char c = 'a';
			for(int j = 0; j < 26; j++) {
				if(set.contains(String.valueOf(c))) {
					c++;
					continue;
				}
				System.out.println(c);
				break;
			}
			}	
		}
	}
}




Compiler output:
Main.java:3: error: cannot find symbol
		Scanner sc = new Scanner(System.in);
		^
  symbol:   class Scanner
  location: class Main
Main.java:3: error: cannot find symbol
		Scanner sc = new Scanner(System.in);
		                 ^
  symbol:   class Scanner
  location: class Main
Main.java:5: error: cannot find symbol
		HashSet<String> set = new HashSet<>();
		^
  symbol:   class HashSet
  location: class Main
Main.java:5: error: cannot find symbol
		HashSet<String> set = new HashSet<>();
		                          ^
  symbol:   class HashSet
  location: class Main
4 errors
Language: C++

#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <cstdlib>
#include <cmath>
#include <numeric>
#include <tuple>
#include <stack>

#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define print(s) cout << s << endl
typedef long long ll;
using namespace std;

int ctoi(char c) {
	if (c >= '0' && c <= '9') {
		return c - '0';
	}
	return 0;
}

int main() {
	string s; cin >> s;
	char x = 'a';
	vector<char> v(s.size());
	rep(i,s.size()){
		v[i] = s[i];
	}
	sort(all(v));
	rep(i,s.size()){
		if (x==v[i]){
			x++;
		}
	}
	cout << (x > 'z'? "None": x) << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:38:25: error: operands to '?:' have different types 'const char*' and 'char'
   38 |         cout << (x > 'z'? "None": x) << endl;
      |                  ~~~~~~~^~~~~~~~~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string s;
  cin>>s;
  string ans="None";
  for(int i=0;i<26;i++){
    for(int j=0;j<s.size();j++){
      bool b=true;
      if((char)('a'+1)==s.at(j)){b=false;}
    }
    if(b){ans=(char)('a'+1);}
  }
  cout<<ans;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:12:8: error: 'b' was not declared in this scope
   12 |     if(b){ans=(char)('a'+1);}
      |        ^
Language: C++

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

int main() {
	string s;
  	cin >> s;
  	int len = s.size();
  
  	vector<char> vec(len);
  
  	for(int i = 0; i < len; i++) {
    	cin >> vec.a(i);
    }
  
  	vector<int> ans(26,0);
  
  	for(int i = 0; i < len; i++) {
    	ans.at(vec.at(i) - 97)++;
    }
  
  	bool all = true;
  
  	for(int i = 0; i < 26; i++) {
    	if(ans.at(i) == 0) {
        	cout << (char)(i + 97) << endl;
          	all = false;
          	break;
        }
    }
  
  	if(all) cout << "None" << endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:12:20: error: 'class std::vector<char>' has no member named 'a'; did you mean 'at'?
   12 |         cin >> vec.a(i);
      |                    ^
      |                    at
Language: C++

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


int main(){
  string S;
  cin >> S;
  sort(S.begin(), S.end());
  erase(unique(S.begin(), S.end()), S.end());
  char t = 'a';
  for(auto& s : S){
    if(s!=t){
      cout << t << endl;
      return 0;
    }
    t++;
  }
  cout << "None" << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'erase' was not declared in this scope
    9 |   erase(unique(S.begin(), S.end()), S.end());
      |   ^~~~~
Language: C++

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

int main() {
  string s; cin >> s;
  sort(s.begin(), s.end());
  bool backet[26] = {false};

  for(char i = 'a'; i <= 'z'; i++) backet[i - 'a'] = true;
  for(int i = 0; i < s.size(); i++) {
    if(backet[i] == flase) {
      cout << backet[i + 'a'] << endl;
      return 0;
    }
  }
  cout << "None" << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:13:21: error: 'flase' was not declared in this scope; did you mean 'fclose'?
   13 |     if(backet[i] == flase) {
      |                     ^~~~~
      |                     fclose
Language: C++

#include <iostream>
#include <algorithm>
#include<string>
using namespace std;
int main() {
    string s;
    string alpha="abcdefghijklmnopqrstuvwxz";
    bool f[26]={false};
    cin>>s;
    for(int i=0;i<s.length(),++i){
        for(int j=0;j<26;++j){
            if(s[i]==alpha[j]){
                f[j]=true;
            }
        }
    }
    for(int i=0;i<26;++i){
        if(!f[i]){
            cout<<alpha[i]<<endl;
            return 0;
        }
    }
    cout<<"None"<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:33: error: expected ';' before ')' token
   10 |     for(int i=0;i<s.length(),++i){
      |                                 ^
      |                                 ;
Language: C++

// std::set を用いた解
#include <bits/std++.h>
using namespace std;

int main() {
  string s;
  cin>>s;
  for(char i='a';i<='z';i++){
    bool f=false;
    for(int j=0;j<s.size();i++){
      if(i==s[j]){
        f=true;
      }
    }
    if(!f){
      cout<<i<<endl;
      return 0;
    }
  }
  cout<<"None"<<endl;
}



Compiler output:
a.cc:2:10: fatal error: bits/std++.h: No such file or directory
    2 | #include <bits/std++.h>
      |          ^~~~~~~~~~~~~~
compilation terminated.
Language: C++

// std::set を用いた解
#include <iostream>
#include <set>
using namespace std;

int main() {
  string s;
  cin>>s;
  for(char i='a';i<='z';i++){
    bool f=false;
    for(int j=0;j<s.size();i++){
      if(i==s.at(j)){
        f=true;
        break;
      }
    }
    if(!f){
      cout<<i<<endl;
      return 0;
    }
  }
  cout<<"None"<<endl;
}
}

Compiler output:
a.cc:24:1: error: expected declaration before '}' token
   24 | }
      | ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
int main(){
  string S;
  cin>>S;
  vector<bool> A(26);
  for(int i=0;i<S.size();i++){
    A[S[i]-'a']++;
  }
  bool f=false;
  for(int i=0;i<26;i++){
    if(A[i]==0){
      cout<<(unsigned char)i+'a'<<endl;
      k=true;
      break;
    }
  }
  if(!k){
    cout<<"None"<<endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:16: error: no 'operator++(int)' declared for postfix '++' [-fpermissive]
    8 |     A[S[i]-'a']++;
      |     ~~~~~~~~~~~^~
a.cc:14:7: error: 'k' was not declared in this scope
   14 |       k=true;
      |       ^
a.cc:18:7: error: 'k' was not declared in this scope
   18 |   if(!k){
      |       ^
Language: C++

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

int main(){
  vector<char> S;
  sort(S.begin(),S.end());
  char ans;
  bool ok=false;
  char i=a;
  while(ok==false&&i<=z){
    for(int j=0;j<S.size();j++){
      if(A[i]==S.at(j))
        i++;
      if else(i!=S.at(j)&&j==S.size()-1){
        ok=true;
        ans=i;
      }
    }
  }
  if(ok=false)
    cout <<"None" <<endl;
  else
    cout <<ans <<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:10: error: 'a' was not declared in this scope
    9 |   char i=a;
      |          ^
a.cc:10:23: error: 'z' was not declared in this scope
   10 |   while(ok==false&&i<=z){
      |                       ^
a.cc:12:10: error: 'A' was not declared in this scope
   12 |       if(A[i]==S.at(j))
      |          ^
a.cc:14:10: error: expected '(' before 'else'
   14 |       if else(i!=S.at(j)&&j==S.size()-1){
      |          ^~~~
      |          (
Language: C++

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

int main(){
  string A="abcdefghijklmnopqrstuvwxyz";
  vector<char> S;
  sort(S.begin(),S.end());
  char ans;
  booi ok=false;
  int i=0;
  while(ok==false&&1<26){
    for(int j=0;j<S.size();j++){
      if(A[i]==S.at(j))
        i++;
      if else(A[i]!=S.at(j)&&j==S.size()-1){
        ok=true;
        ans=A[i];
      }
    }
  }
  if(ok=false)
    cout <<"None" <<endl;
  else
    cout <<ans <<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'booi' was not declared in this scope; did you mean 'bool'?
    9 |   booi ok=false;
      |   ^~~~
      |   bool
a.cc:11:9: error: 'ok' was not declared in this scope
   11 |   while(ok==false&&1<26){
      |         ^~
a.cc:15:10: error: expected '(' before 'else'
   15 |       if else(A[i]!=S.at(j)&&j==S.size()-1){
      |          ^~~~
      |          (
a.cc:21:6: error: 'ok' was not declared in this scope
   21 |   if(ok=false)
      |      ^~
Language: C++

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

int main(){
  string A=abcdefghijklmnopqrstuvwxyz;
  vector<char> S;
  sort(S.begin(),S.end());
  char ans;
  booi ok=false;
  int i=0;
  while(ok==false&&1<26){
    for(int j=0;j<S.size();j++){
      if(A[i]==S.at(j))
        i++;
      if else(A[i]!=S.at(j)&&j==S.size()-1){
        ok=true;
        ans=A[i];
      }
    }
  }
  if(ok=false)
    cout <<"None" <<endl;
  else
    cout <<ans <<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:12: error: 'abcdefghijklmnopqrstuvwxyz' was not declared in this scope
    5 |   string A=abcdefghijklmnopqrstuvwxyz;
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:9:3: error: 'booi' was not declared in this scope; did you mean 'bool'?
    9 |   booi ok=false;
      |   ^~~~
      |   bool
a.cc:11:9: error: 'ok' was not declared in this scope
   11 |   while(ok==false&&1<26){
      |         ^~
a.cc:15:10: error: expected '(' before 'else'
   15 |       if else(A[i]!=S.at(j)&&j==S.size()-1){
      |          ^~~~
      |          (
a.cc:21:6: error: 'ok' was not declared in this scope
   21 |   if(ok=false)
      |      ^~
Language: C++

#include <iostream>
#include <string>
using namespace std;
int main(){
  string s;
  cin >> s;
  
  for (char c = 'a'; c <= 'z'; c++){
    if (find(s.begin(), s.end(), c) == s.end()){
      cout << c << endl;
      return 0;
    }
  }
  cout << "None" << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:13: error: no matching function for call to 'find(std::__cxx11::basic_string<char>::iterator, std::__cxx11::basic_string<char>::iterator, char&)'
    9 |     if (find(s.begin(), s.end(), c) == s.end()){
      |         ~~~~^~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,
                 from /usr/include/c++/14/ios:46,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/streambuf_iterator.h:435:5: note: candidate: 'template<class _CharT2> typename __gnu_cxx::__enable_if<std::__is_char<_CharT2>::__value, std::istreambuf_iterator<_CharT> >::__type std::find(istreambuf_iterator<_CharT>, istreambuf_iterator<_CharT>, const _CharT2&)'
  435 |     find(istreambuf_iterator<_CharT> __first,
      |     ^~~~
/usr/include/c++/14/bits/streambuf_iterator.h:435:5: note:   template argument deduction/substitution failed:
a.cc:9:13: note:   '__gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >' is not derived from 'std::istreambuf_iterator<_CharT>'
    9 |     if (find(s.begin(), s.end(), c) == s.end()){
      |         ~~~~^~~~~~~~~~~~~~~~~~~~~~~
Language: C++

#include<iostream>
using namespace std;

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

  for ( int i = 0; i < 26; i++){
    char moji = 'a' + i;
    bool flag = false;
    for(int j = 0; j < s.size(); j++){
      if(s[j] == moji){
        flag = true;
      }
    }
    if(!flag)cout<<moji<<endl;
    return 0;
    }
  }
  cout << "None" <<endl;
  return 0;

}



Compiler output:
a.cc:20:3: error: 'cout' does not name a type
   20 |   cout << "None" <<endl;
      |   ^~~~
a.cc:21:3: error: expected unqualified-id before 'return'
   21 |   return 0;
      |   ^~~~~~
a.cc:23:1: error: expected declaration before '}' token
   23 | }
      | ^
Language: C++

#include <bits/stdc++.h>
#define REP(i,n) for(int i=0;i<n;i++)
long long inf=(long long)1E17;
using namespace std;
int main(){
  vector<bool> a(26,false);
  string s;
  cin>>s;
  REP(i,s.size()){
    a[s[i]-'a'] = ture;
  }
  char c;
  REP(i,26){
    if(!a[i]){
      c = 'a'+i;
      cout<<c<<endl;
      return 0;
    }
  }
  cout<<"None"<<endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:19: error: 'ture' was not declared in this scope
   10 |     a[s[i]-'a'] = ture;
      |                   ^~~~
Language: C++

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

  int main(){
    string S;
    cin >> S;
    int a[26]={};
    string r;
    for (int i=0;i<S.size();i++){
      a[S[i]-'a']=1
    }
    for (int i=0;i<26;i++){
      if (a[i]==0){
        char c=i+'a';
        cout << c << endl;
        return 0;
      }
    }
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:10:20: error: expected ';' before '}' token
   10 |       a[S[i]-'a']=1
      |                    ^
      |                    ;
   11 |     }
      |     ~