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

#include<stdio.h>
int main(){
  int n;
  char s[100],t[100];
  scanf("%d",&n);
  for (i = 0; i < n; i++) {
    printf("%c%c",s[i],t[i]);
  }
  printf("\n");
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:6:8: error: 'i' undeclared (first use in this function)
    6 |   for (i = 0; i < n; i++) {
      |        ^
main.c:6:8: note: each undeclared identifier is reported only once for each function it appears in
Language: C

#include<iostream>
#include<cstring>
using namespace std;
int main(int argc, const char* argv[])
{
	int a;
	cin >> a;
	char A[200];
	char B[200];
	cin >> A;
	cin >> B;
	char C[300];
	for (int i = 0, t=0; i < 2 * (a-1)+1,t<a; i = i + 2,t=t+1)
	{
		C[i] = A[t];
		C[i + 1] = B[t];
	}
	C[2 * a] = '\0';
	cout << C;


	return 0;
}

Compiler output:
main.c:1:9: fatal error: iostream: No such file or directory
    1 | #include<iostream>
      |         ^~~~~~~~~~
compilation terminated.
Language: C++

#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;
using P = pair<int, int>;
constexpr ld EPS = 1e-12;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr int MOD = 1e9 + 7;

template <typename T>
void printv(const vector<T> &v) {
  int sz = v.size();
  for (int i = 0; i < sz; i++) {
    cout << v[i] << " \n"[i == sz - 1];
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n;
  string s, t;
  cin >> s >> t;
  string ret = "";
  for (int i = 0; I < n; i++) {
    ret += s[i];
    ret += t[i];
  }
  cout << ret << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:28:19: error: 'I' was not declared in this scope
   28 |   for (int i = 0; I < n; i++) {
      |                   ^
Language: C++

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

int main(){
  int n;
  char s[102],t[101],ans[201];
  cin >> n;
  for(int i=0;i<n;i++)
    cin >> s[i];
  for(int i=0;i<n;i++)
    cin >> t[i];
  for(int i=0;i<n;i++)
    ans = ans+s[i]+t[i];
  cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:9: error: incompatible types in assignment of 'char*' to 'char [201]'
   13 |     ans = ans+s[i]+t[i];
      |     ~~~~^~~~~~~~~~~~~~~
Language: C++

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

int main() {
  int N;
  string S,T;
  vector<string> answer(2*N);
  int i=0;
  while i<N{
    string.at(i)=S.at(i);
    string.at(i+1)=T.at(i+1);
    i=i+2;
  }
  
  for(int a=0;a<N*2;a=a+2){
    cout<<string.at(i);
  }
  cout<<endl;
    
  
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:9: error: expected '(' before 'i'
    9 |   while i<N{
      |         ^
      |         (
a.cc:9:12: error: expected ')' before '{' token
    9 |   while i<N{
      |         ~  ^
      |            )
a.cc:10:11: error: expected unqualified-id before '.' token
   10 |     string.at(i)=S.at(i);
      |           ^
a.cc:11:11: error: expected unqualified-id before '.' token
   11 |     string.at(i+1)=T.at(i+1);
      |           ^
a.cc:16:17: error: expected primary-expression before '.' token
   16 |     cout<<string.at(i);
      |                 ^
Language: C++

#include<iostream>

using namespace std;

int main(){
  int N,i;
  Double S,T,A;
  
     cin>>N>>S>>T;              //外部入力読み込み方法
   
  Double S2 =new int[N];
  Double T2 =new int[N];      //動的配列割り当て


  for(i =1; i<=N;i++){
    
     S2[i]=S % 10; //Sを10で割った時のあまり=1桁目の数
　　 T2[i] =T % 10; // Tを10で割った時のあまり
　  
  }

  for (i=1; i<=2*N; i++){

    A= A+T[i]*pow(10,2*(i-1));
    A=A+S[i]*pow(10,2*i-1);
  }  

cout <<A ;

 return 0;
}


Compiler output:
a.cc:18:1: error: extended character 　 is not valid in an identifier
   18 | 　　 T2[i] =T % 10; // Tを10で割った時のあまり
      | ^
a.cc:18:1: error: extended character 　 is not valid in an identifier
a.cc:19:1: error: extended character 　 is not valid in an identifier
   19 | 　
      | ^
a.cc: In function 'int main()':
a.cc:7:3: error: 'Double' was not declared in this scope; did you mean 'double'?
    7 |   Double S,T,A;
      |   ^~~~~~
      |   double
a.cc:9:14: error: 'S' was not declared in this scope
    9 |      cin>>N>>S>>T;              //外部入力読み込み方法
      |              ^
a.cc:9:17: error: 'T' was not declared in this scope
    9 |      cin>>N>>S>>T;              //外部入力読み込み方法
      |                 ^
a.cc:11:9: error: expected ';' before 'S2'
   11 |   Double S2 =new int[N];
      |         ^~~
      |         ;
a.cc:12:9: error: expected ';' before 'T2'
   12 |   Double T2 =new int[N];      //動的配列割り当て
      |         ^~~
      |         ;
a.cc:17:6: error: 'S2' was not declared in this scope
   17 |      S2[i]=S % 10; //Sを10で割った時のあまり=1桁目の数
      |      ^~
a.cc:18:1: error: '\U00003000\U00003000' was not declared in this scope
   18 | 　　 T2[i] =T % 10; // Tを10で割った時のあまり
      | ^~~~
a.cc:19:1: error: '\U00003000' was not declared in this scope
   19 | 　
      | ^~
a.cc:24:5: error: 'A' was not declared in this scope
   24 |     A= A+T[i]*pow(10,2*(i-1));
      |     ^
a.cc:24:15: error: 'pow' was not declared in this scope
   24 |     A= A+T[i]*pow(10,2*(i-1));
      |               ^~~
a.cc:28:8: error: 'A' was not declared in this scope
   28 | cout <<A ;
      |        ^
Language: C++

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

int main()
{
  int a,i;
  char *S;
  char *T;
  char *U;
  cin >> a;
  
  char s,t,u;
  
  cin >>s;
  cin >>t; 
  S=&s;
  T=&t;
  U=&u;
  
  for (i=0;i<a;i++)
  {
    *U=*S;
    *(++U)=*T;
    *U++;
    *S++;
    *T++;
  }
 cout << *u;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:10: error: invalid type argument of unary '*' (have 'char')
   28 |  cout << *u;
      |          ^~
Language: C++

#include<fstream>
#include<string>
#include<iostream>
#include<sstream>
#include<iterator>
#include<cmath>
#include<stdio.h>

using namespace std;

int main(){
 int N;
 cin >> N;
string S;
string T;
 cin >> S >> T
  int i;
  char c;
  char d;
  for(i=0;i<N;i++){
   c = S[i];
   d = T[i];
   cout << c << d;} 
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:15: error: expected ';' before 'int'
   16 |  cin >> S >> T
      |               ^
      |               ;
   17 |   int i;
      |   ~~~          
a.cc:20:7: error: 'i' was not declared in this scope
   20 |   for(i=0;i<N;i++){
      |       ^
Language: Java

import java.util.*;

public class Main{
  public static void main(String[]args){

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();
   String C;
for(int i=0;i<A.length();i++){
  C=C+A.charAt(i)+B.charAt(i);
}
  System.out.println("C");
  }
}

                  


Compiler output:
Main.java:11: error: variable C might not have been initialized
  C=C+A.charAt(i)+B.charAt(i);
    ^
1 error
Language: C++

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

Compiler output:
a.cc:2:20: error: expected ';' before 'int'
    2 | using namespace std
      |                    ^
      |                    ;
    3 | int main()
      | ~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
  long long a;
  cin>>a;
  string s,t;
  cin>>s>>t;
  for(i=0;i<a;i++)
  {
    cout<<s[i]<<t[i];
  }
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:9:7: error: 'i' was not declared in this scope
    9 |   for(i=0;i<a;i++)
      |       ^
Language: C++

#include<bits/stdc++.h>
#include<string>
using namespace std;
//max=({});

int main() {
	int n;
	cin >> n;
	string S, T;
	cin >> S >> T;
	string ans= 'S[0]' + 'T[0]';
	for (int i = 1;i < n;++i) {
		ans += 'S[i]';
		ans += 'T[i]';
	}
	cout << "ans" << endl;
}


Compiler output:
a.cc:11:21: warning: multi-character character constant [-Wmultichar]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                     ^~~~~~
a.cc:11:30: warning: multi-character character constant [-Wmultichar]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                              ^~~~~~
a.cc:13:24: warning: multi-character character constant [-Wmultichar]
   13 |                 ans += 'S[i]';
      |                        ^~~~~~
a.cc:14:24: warning: multi-character character constant [-Wmultichar]
   14 |                 ans += 'T[i]';
      |                        ^~~~~~
a.cc: In function 'int main()':
a.cc:11:28: warning: integer overflow in expression of type 'int' results in '-1481219910' [-Woverflow]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                     ~~~~~~~^~~~~~~~
a.cc:11:28: error: conversion from 'int' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
a.cc:13:24: warning: overflow in conversion from 'int' to 'char' changes value from '1398499677' to '93' [-Woverflow]
   13 |                 ans += 'S[i]';
      |                        ^~~~~~
a.cc:14:24: warning: overflow in conversion from 'int' to 'char' changes value from '1415276893' to '93' [-Woverflow]
   14 |                 ans += 'T[i]';
      |                        ^~~~~~
Language: Java

import java.util.*;

public class Main{
  public static void main(String[]args){

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();
   String C;
for(int i=0;i<A.length;i++){
  C=C+A.charAt(i)+B.charAt(i);
}
  System.out.println("C");
  }
}

                  


Compiler output:
Main.java:10: error: cannot find symbol
for(int i=0;i<A.length;i++){
               ^
  symbol:   variable length
  location: variable A of type String
1 error
Language: C++

#include<stdc++.h>
using namespace std;
int main()
{
  long long a;
  cin>>a;
  string s,t;
  cin>>s>>t;
  for(i=0;i<a;i++)
  {
    cout<<s[i]<<t[i];
  }
  return 0;
}


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

#include <stdio.h>
int main()
{
    
    int n,i;
    scanf("%d",&n);
    char a[n]={'0'};
	char b[n]={'0'};
	scanf("%s",&a);
	scanf("%s",&b);
	for(i=0;i<n;i++)
	{
		printf("%c",a[i]);
		printf("%c",b[i]);
	}
    return 0;
}


Compiler output:
main.c: In function 'main':
main.c:7:15: error: variable-sized object may not be initialized except with an empty initializer
    7 |     char a[n]={'0'};
      |               ^
main.c:8:19: error: variable-sized object may not be initialized except with an empty initializer
    8 |         char b[n]={'0'};
      |                   ^
Language: Java

import java.util.*;

public class Main{
  public static void main(String[]args){

    Scanner sc=new Scanner(System.in);
    String A=sc.next();
    String B=sc.next();
   String C;
for(int i=0;i<A.lemgth;i++){
  C=C+A.charAt(i)+B.charAt(i);
}
  System.out.println("C");
  }
}

                  


Compiler output:
Main.java:10: error: cannot find symbol
for(int i=0;i<A.lemgth;i++){
               ^
  symbol:   variable lemgth
  location: variable A of type String
1 error
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  long long int len;
  cin>>len;
   cin.ignore(numeric_limits<streamsize>::max(), '\n');
  string s;
  getline(cin,s);
  // string t;
 // for()
 // getline()
  string ne;
  for(int i=0;i<len;i++){
    ne.push_back(s[i]);
    ne.push_back(s[i+len+1]);
  }
  for(int i=0;i<new.size();i++){
    cout<<ne[i];
  }
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:20: error: expected type-specifier before '.' token
   17 |   for(int i=0;i<new.size();i++){
      |                    ^
a.cc:17:20: error: expected ';' before '.' token
   17 |   for(int i=0;i<new.size();i++){
      |                    ^
      |                    ;
a.cc:17:20: error: expected primary-expression before '.' token
a.cc:17:27: error: expected ')' before ';' token
   17 |   for(int i=0;i<new.size();i++){
      |      ~                    ^
      |                           )
a.cc:17:28: error: 'i' was not declared in this scope
   17 |   for(int i=0;i<new.size();i++){
      |                            ^
Language: Java

import java.util.Scanner;

class Main{
public static void main(String[] args){
Scanner scan=new Scanner(System.in);
int na=scan.nectInt();  
String nb=scan.next();
String nc=scan.next();
  
String[] mb=nb.split("");
String[] mc=nc.split("");
  
String[] md=new String[2*na];
for(int i=0;i<na;i++){
    md[2*i]=mb[i];
    md[2*i+1]=mc[i];
}

  String nd=String.join("",md);
  System.out.println(nd);

}
}

Compiler output:
Main.java:6: error: cannot find symbol
int na=scan.nectInt();  
           ^
  symbol:   method nectInt()
  location: variable scan of type Scanner
1 error
Language: C++

#include <iostream>
#include <string>

using namespace std;

int main(int argc, char* argv[]) {
  int N;
  cin >> N;
  string S, T;
  cint >> S >> T;
  string ans;
  ans.reserve(N*2);
  for(int i = 0; i < N; ++i) {
    ans += S[i];
    ans += T[i];
  }
  cout << ans << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main(int, char**)':
a.cc:10:3: error: 'cint' was not declared in this scope; did you mean 'uint'?
   10 |   cint >> S >> T;
      |   ^~~~
      |   uint
Language: C++

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

int main() {
  int n;
  string s,t;
  cin >> n >> s >> t;
  
  for(int i=0;i<n;i++) {
     cout << at.s(i) << at.t(i);
  }
  cout << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:14: error: 'at' was not declared in this scope; did you mean 't'?
   10 |      cout << at.s(i) << at.t(i);
      |              ^~
      |              t
Language: C++

//Lion's Sin Escanor 

#include<bits/stdc++.h>
using namespace std;
     
     
//#define SPEED ios::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define ll long long
#define sd(x) scanf("%d",&x)
#define sld(x) scanf("%lld",&x)
#define pld(x) printf("%lld\n",x)
#define pd(x) printf("%d\n",x)
#define moder 1000000007
#define forn(i,n) for(int i = 0; i < n ; i++)

ll moding( ll x , ll y ){
   
    ll ans = x % y;

    if(ans < 0)ans = ans + y ;

    return ans ;

}


bool isprime(ll n){
    if(n==2) return true;
    if(n==3) return true;
    if(n%2 == 0) return false;
    if(n%3 == 0) return false;

    ll i = 5,w=2;

    while(i*i <= n){
        if(n%i == 0)return false;

        i += w;
        w = 6 - w;
    }

    return true;
}

ll cmp(string s1 , string s2){
    // 1 for diff
    // 0 for same 

    int n = s1.size();
    int m = s2.size();

    if(n!=m)return 1;

    forn(i,n)
        if(s1[i] != s2[i])return 1;


    return 0; // SAME
}




int main(){

    int n; cin >> n;

    string s , t; 
    cin >> s >> t;

    forn(i,0,n){
        cout<< s[i] << t[i];
    }

    cout << endl;


           
     
     
        
    return 0;
}
      
       

Compiler output:
a.cc:71:15: error: macro "forn" passed 3 arguments, but takes just 2
   71 |     forn(i,0,n){
      |               ^
a.cc:14:9: note: macro "forn" defined here
   14 | #define forn(i,n) for(int i = 0; i < n ; i++)
      |         ^~~~
a.cc: In function 'int main()':
a.cc:71:5: error: 'forn' was not declared in this scope
   71 |     forn(i,0,n){
      |     ^~~~
Language: C

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

Compiler output:
main.c: In function 'main':
main.c:7:15: error: variable-sized object may not be initialized except with an empty initializer
    7 |     char a[n]={0};
      |               ^
main.c:8:19: error: variable-sized object may not be initialized except with an empty initializer
    8 |         char b[n]={0};
      |                   ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string a,b;
  cin>>a>>b;
  int n = s.size();
  char* x = new char[2*n+1];
  for(int i=0;i<n;i=i+2){
    x[i] = a[i];
  }
  for(int i=1;i<n;i=i+2){
    x[i] = b[i];
  }
  for(int i=0;i<2*n;i++){
    cout<<x[i];
  }
  return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:6:11: error: 's' was not declared in this scope
    6 |   int n = s.size();
      |           ^
Language: C++

#include<bits/stdc++.h>
#include<string>
using namespace std;
//max=({});

int main() {
	int n;
	cin >> n;
	string S, T;
	cin >> S >> T;
	string ans= 'S[0]' + 'T[0]';
	for (int i = 1;i < n;++i) {
		ans += 'S[i]';
		ans += 'T[i]';
	}
	cout << ans << endl;
}


Compiler output:
a.cc:11:21: warning: multi-character character constant [-Wmultichar]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                     ^~~~~~
a.cc:11:30: warning: multi-character character constant [-Wmultichar]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                              ^~~~~~
a.cc:13:24: warning: multi-character character constant [-Wmultichar]
   13 |                 ans += 'S[i]';
      |                        ^~~~~~
a.cc:14:24: warning: multi-character character constant [-Wmultichar]
   14 |                 ans += 'T[i]';
      |                        ^~~~~~
a.cc: In function 'int main()':
a.cc:11:28: warning: integer overflow in expression of type 'int' results in '-1481219910' [-Woverflow]
   11 |         string ans= 'S[0]' + 'T[0]';
      |                     ~~~~~~~^~~~~~~~
a.cc:11:28: error: conversion from 'int' to non-scalar type 'std::string' {aka 'std::__cxx11::basic_string<char>'} requested
a.cc:13:24: warning: overflow in conversion from 'int' to 'char' changes value from '1398499677' to '93' [-Woverflow]
   13 |                 ans += 'S[i]';
      |                        ^~~~~~
a.cc:14:24: warning: overflow in conversion from 'int' to 'char' changes value from '1415276893' to '93' [-Woverflow]
   14 |                 ans += 'T[i]';
      |                        ^~~~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string a,b;
  cin>>a>>b;
  int n = strlen(a);
  char* x = new char[2*n+1];
  for(int i=0;i<n;i=i+2){
    x[i] = a[i];
  }
  for(int i=1;i<n;i=i+2){
    x[i] = b[i];
  }
  for(int i=0;i<2*n;i++){
    cout<<x[i];
  }
  return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:6:18: error: cannot convert 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'const char*'
    6 |   int n = strlen(a);
      |                  ^
      |                  |
      |                  std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/include/c++/14/cstring:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:121,
                 from a.cc:1:
/usr/include/string.h:407:35: note:   initializing argument 1 of 'size_t strlen(const char*)'
  407 | extern size_t strlen (const char *__s)
      |                       ~~~~~~~~~~~~^~~
Language: C++

#include<iostream>
using namespace std;

int main(){
  cin >> N;
  cin >> S >> T;

  for(int i = 0;i<N;i++){
      cout << S[i] << T[i];
  }
return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:10: error: 'N' was not declared in this scope
    5 |   cin >> N;
      |          ^
a.cc:6:10: error: 'S' was not declared in this scope
    6 |   cin >> S >> T;
      |          ^
a.cc:6:15: error: 'T' was not declared in this scope
    6 |   cin >> S >> T;
      |               ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main
{
	int n;
    cin >> n;
	string a,b,s;
    cin >> a >> b;
    for(int i=0;i<n;i++)
    {
    	s += a[i];
        s += b[i];
    }
    cout << s;
    return 0;
}


Compiler output:
a.cc:3:5: error: cannot declare '::main' to be a global variable
    3 | int main
      |     ^~~~
a.cc:5:9: error: expected primary-expression before 'int'
    5 |         int n;
      |         ^~~
a.cc:5:9: error: expected '}' before 'int'
a.cc:4:1: note: to match this '{'
    4 | {
      | ^
a.cc:6:5: error: 'cin' does not name a type
    6 |     cin >> n;
      |     ^~~
a.cc:8:5: error: 'cin' does not name a type
    8 |     cin >> a >> b;
      |     ^~~
a.cc:9:5: error: expected unqualified-id before 'for'
    9 |     for(int i=0;i<n;i++)
      |     ^~~
a.cc:9:17: error: 'i' does not name a type
    9 |     for(int i=0;i<n;i++)
      |                 ^
a.cc:9:21: error: 'i' does not name a type
    9 |     for(int i=0;i<n;i++)
      |                     ^
a.cc:14:5: error: 'cout' does not name a type
   14 |     cout << s;
      |     ^~~~
a.cc:15:5: error: expected unqualified-id before 'return'
   15 |     return 0;
      |     ^~~~~~
a.cc:16:1: error: expected declaration before '}' token
   16 | }
      | ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  string a,b;
  cin>>a>>b;
  char* x = new char[2*n+1];
  for(int i=0;i<n;i=i+2){
    x[i] = a[i];
  }
  for(int i=1;i<n;i=i+2){
    x[i] = b[i];
  }
  for(int i=0;i<2*n;i++){
    cout<<x[i];
  }
  return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:6:24: error: 'n' was not declared in this scope
    6 |   char* x = new char[2*n+1];
      |                        ^
Language: C++

#include<bits/sdtc++.h>
using namespace std;
int main(){
  string a,b;
  cin>>a>>b;
  char* x = new char[2*n+1];
  for(int i=0;i<n;i=i+2){
    x[i] = a[i];
  }
  for(int i=1;i<n;i=i+2){
    x[i] = b[i];
  }
  for(int i=0;i<2*n;i++){
    cout<<x[i];
  }
  return 0;
} 

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

#include <iostream>

#define REP(i,n) for(int i=0;i<n;++i)
using namespace std;

int main(){
  int n;
  string s, t;
  vector<char> r;
  cin >> n >> s >> t;
  REP(i, n) {
    cout << s[i] << t[i];
  }
  cout << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'vector' was not declared in this scope
    9 |   vector<char> r;
      |   ^~~~~~
a.cc:2:1: note: 'std::vector' is defined in header '<vector>'; this is probably fixable by adding '#include <vector>'
    1 | #include <iostream>
  +++ |+#include <vector>
    2 | 
a.cc:9:10: error: expected primary-expression before 'char'
    9 |   vector<char> r;
      |          ^~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
 
  int a;
  string b,c;

  cin >> a;
  cin >> b;
  cin >> c;
  
  for (int i = 0; i < a; i++) {
	  cout << b.at(i); << endl;
	  cout << c.at(i); << endl;
}
 
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:28: error: expected primary-expression before '<<' token
   14 |           cout << b.at(i); << endl;
      |                            ^~
a.cc:15:28: error: expected primary-expression before '<<' token
   15 |           cout << c.at(i); << endl;
      |                            ^~
Language: C++

#include<iostream>
#include<string>

using namespace std;

int main(void)
{
  int n;
  string s,t;
  
  cin>>n;
  cin>>s>>t;
  
  string ans;
  
  for(int i=0;i<2n-2;i+=2)
  {
    ans[i]=s[i];
    ans[i+1]=t[i];
  }
  
  cout<<ans<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:17: error: unable to find numeric literal operator 'operator""n'
   16 |   for(int i=0;i<2n-2;i+=2)
      |                 ^~
Language: C++

#include<iostream>
using namespace std;
int main(){
  	int n;
  	string a,b;
  	
  	while(cin>>n){
      	string str="";
      	cin>>a>>b;
    	for(int i=0;i<n;i++){
        	str += a[i];
          	str += b[i];
        }
      cout<<str<<endl;
    }
	retrun 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:9: error: 'retrun' was not declared in this scope
   16 |         retrun 0;
      |         ^~~~~~
Language: C++

#include <iostream>

using namespace std;

int main() {
  int a;
  str s, t;
  cin >> a;

    for(int i=0;i <a; i++){
        cout <<s[i] << t[i]<< endl; 
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:3: error: 'str' was not declared in this scope; did you mean 'std'?
    7 |   str s, t;
      |   ^~~
      |   std
a.cc:11:16: error: 's' was not declared in this scope
   11 |         cout <<s[i] << t[i]<< endl;
      |                ^
a.cc:11:24: error: 't' was not declared in this scope
   11 |         cout <<s[i] << t[i]<< endl;
      |                        ^
Language: C++

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

#include <iostream>
#include <set>
using namespace std;
int main()
{   int n;
cin >> n;
    string a;
    string b;
    cin >> a >> b;
    for(int i=0;i<n;i++){
        cout << a[i] << b[i];
    }
    cout << endl;
    return 0;
}

Compiler output:
a.cc:1:10: error: #include expects "FILENAME" or <FILENAME>
    1 | #include #include <iostream>
      |          ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
string a,b;
int main() {
  	cint >>a>>b;
  	string ans="";
  
   for(int i=0;i<a.length();i++) {
     ans += a[i]+b[i];
   }
  
  cout << ans << endl;
	return 0;  
|

Compiler output:
a.cc: In function 'int main()':
a.cc:6:9: error: 'cint' was not declared in this scope; did you mean 'uint'?
    6 |         cint >>a>>b;
      |         ^~~~
      |         uint
a.cc:15:1: error: expected primary-expression before '|' token
   15 | |
      | ^
a.cc:15:2: error: expected primary-expression at end of input
   15 | |
      |  ^
a.cc:15:2: error: expected '}' at end of input
a.cc:5:12: note: to match this '{'
    5 | int main() {
      |            ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
 
  int a;
  string b,c;

  cin >> a;
  cin >> b;
  cin >> c;
  
  for (int i = 0; i < a; i++) {
	  cout << a.at(i); << endl;
	  cout << b.at(i); << endl;
}
 
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:21: error: request for member 'at' in 'a', which is of non-class type 'int'
   14 |           cout << a.at(i); << endl;
      |                     ^~
a.cc:14:28: error: expected primary-expression before '<<' token
   14 |           cout << a.at(i); << endl;
      |                            ^~
a.cc:15:28: error: expected primary-expression before '<<' token
   15 |           cout << b.at(i); << endl;
      |                            ^~
Language: C++

#include <iostream>
#incldue <string>

using namespace std;

int main() {
  int n;
  string str1, str2, str3;
  cin >> n >> str1 >> str2;
  
  for(int i = 0; i < n*2;){
    str3[i]=str1[i];
    i++;
    str3[i]=str2[i];
    i++;
  }
  
  cout << str3 << endl;
  
}
  

Compiler output:
a.cc:2:2: error: invalid preprocessing directive #incldue; did you mean #include?
    2 | #incldue <string>
      |  ^~~~~~~
      |  include
Language: C++

#include<iostream>
using namespace std;
int main(){
  	int a;
  	string a,b;
  	
  	while(cin>>a){
      	string str="";
      	cin>>a>>b;
    	for(int i=0;i<a;i++){
        	str += a[i];
          	str += b[i];
        }
      cout<<str<<endl;
    }
	retrun 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:16: error: conflicting declaration 'std::string a'
    5 |         string a,b;
      |                ^
a.cc:4:13: note: previous declaration as 'int a'
    4 |         int a;
      |             ^
a.cc:11:25: error: invalid types 'int[int]' for array subscript
   11 |                 str += a[i];
      |                         ^
a.cc:16:9: error: 'retrun' was not declared in this scope
   16 |         retrun 0;
      |         ^~~~~~
Language: C++

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

string a,b;
int main() {
  	cint >>a>>b;
  	string ans;
  
   for(int i=0;i<a.length();i++) {
     ans += a[i]+b[i];
   }
  
  cout << ans << endl;
	return 0;  
|

Compiler output:
a.cc: In function 'int main()':
a.cc:6:9: error: 'cint' was not declared in this scope; did you mean 'uint'?
    6 |         cint >>a>>b;
      |         ^~~~
      |         uint
a.cc:15:1: error: expected primary-expression before '|' token
   15 | |
      | ^
a.cc:15:2: error: expected primary-expression at end of input
   15 | |
      |  ^
a.cc:15:2: error: expected '}' at end of input
a.cc:5:12: note: to match this '{'
    5 | int main() {
      |            ^
Language: C++

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

int main() {T#include <bits/stdc++.h>
using namespace std;

int main() {
  int a;
  cin>>a;
  string S,T;
  cin>>S>>T;
  for(int i=0;i<a;i++){
    cout<<S[i]<<T[i];
  }
}

Compiler output:
a.cc:4:14: error: stray '#' in program
    4 | int main() {T#include <bits/stdc++.h>
      |              ^
a.cc: In function 'int main()':
a.cc:4:13: error: 'T' was not declared in this scope
    4 | int main() {T#include <bits/stdc++.h>
      |             ^
a.cc:7:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
    7 | int main() {
      |         ^~
a.cc:7:9: note: remove parentheses to default-initialize a variable
    7 | int main() {
      |         ^~
      |         --
a.cc:7:9: note: or replace parentheses with braces to value-initialize a variable
a.cc:7:12: error: a function-definition is not allowed here before '{' token
    7 | int main() {
      |            ^
a.cc:15:2: error: expected '}' at end of input
   15 | }
      |  ^
a.cc:4:12: note: to match this '{'
    4 | int main() {T#include <bits/stdc++.h>
      |            ^
Language: C++

#include<iostream>

using namespace std;

int main() {

  int n;

  cin>>n;

  string s, t;

  cin>>s>>t;

  for(int i(0) ;i<n;++i) {

    if(i%2==1) {

      cout<<t[i];

    }

    else{

      cout<<s[i];

      }

  }



Compiler output:
a.cc: In function 'int main()':
a.cc:29:4: error: expected '}' at end of input
   29 |   }
      |    ^
a.cc:5:12: note: to match this '{'
    5 | int main() {
      |            ^
Language: C++

N =int(input())

A,B = input().split()
s = ""
for i in range(N*2):
  if i%2 == 0:
    s+=A[i//2]
  else:
    s+=B[i//2]   
print(s)


Compiler output:
a.cc:1:1: error: 'N' does not name a type
    1 | N =int(input())
      | ^
Language: C++

#include<iostream>
#include<bits/stdc++.h>
using namsepace std;
int main(){
  int n;
  cin>>n;
  string s,t;
  cin>>s>>t;
  string a;
  int k=0;
  for(int i=0;i<n;i++){
  a[k++]=s[0];
    a[k++]=t[0];
  
  }
  a[k]='\0';
  cout<<a<<endl;
}

Compiler output:
a.cc:3:7: error: expected nested-name-specifier before 'namsepace'
    3 | using namsepace std;
      |       ^~~~~~~~~
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |   cin>>n;
      |   ^~~
      |   std::cin
In file included from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:7:3: error: 'string' was not declared in this scope
    7 |   string s,t;
      |   ^~~~~~
a.cc:7:3: 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:
/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:8:8: error: 's' was not declared in this scope
    8 |   cin>>s>>t;
      |        ^
a.cc:8:11: error: 't' was not declared in this scope
    8 |   cin>>s>>t;
      |           ^
a.cc:9:9: error: expected ';' before 'a'
    9 |   string a;
      |         ^~
      |         ;
a.cc:12:3: error: 'a' was not declared in this scope
   12 |   a[k++]=s[0];
      |   ^
a.cc:16:3: error: 'a' was not declared in this scope
   16 |   a[k]='\0';
      |   ^
a.cc:17:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   17 |   cout<<a<<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:17:12: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   17 |   cout<<a<<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>
using namespace std;

int main() {
  int n;
  cin>>n;
  string s, t;
  cin>>s>>t;
  for(int i(0) ;i<n;++i) {
    if(i%2==1) {
      cout<<b[i];
    }
    else{
      cout<<a[i];
      }
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:11:13: error: 'b' was not declared in this scope
   11 |       cout<<b[i];
      |             ^
a.cc:14:13: error: 'a' was not declared in this scope
   14 |       cout<<a[i];
      |             ^
a.cc:16:4: error: expected '}' at end of input
   16 |   }
      |    ^
a.cc:4:12: note: to match this '{'
    4 | int main() {
      |            ^
Language: C++

#include<bits/stdc++.h>

using namespace std;

int main()
{
  string str1, str2;
  cin >> str1 >> str2;
  for(int i=0; i<N; i++)
  {
    cout << str1[i] << str2[i];
  }
  
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:18: error: 'N' was not declared in this scope
    9 |   for(int i=0; i<N; i++)
      |                  ^
Language: C++

N =int(input())

A,B = input().split()
s = ""
for i in range(N*2):
  if i%2 == 0:
    s+=A[i//2]
  else:
    s+=B[i//2]   
print(s)

Compiler output:
a.cc:1:1: error: 'N' does not name a type
    1 | N =int(input())
      | ^
Language: C++

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pcc pair<char,char>
#define vi vector <int>
#define vl vector <ll>
#define sd(x) scanf("%d",&x)
#define slld(x) scanf("%lld",&x)
#define pd(x) printf("%d",x)
#define plld(x) printf("%lld",x)
#define pds(x) printf("%d ",x)
#define pllds(x) printf("%lld ",x)
#define pdn(x) printf("%d\n",x)
#define plldn(x) printf("%lld\n",x)
#define INF 2e9
#define INFLL 4e18
using namespace std;
ll powmod(ll base,ll exponent,ll mod){ // with mod < 1e9
	ll ans=1;
	while(exponent){
		if(exponent&1)ans=(ans*base)%mod;
		base=(base*base)%mod;
		exponent/=2;
	}
	return ans;
}
ll gcd(ll a, ll b){
	if(b==0) return a;
	else return gcd(b,a%b);
}
const int upperlimit = 1e6+100;
const int mod = 1e9+7;
int main() {
	int n;
	string s1,s2;
	cin >> n >> s1 >> s2;
	for(int i = 0; i < 2n; i++){
		if(i&1) cout << s2[i/2];
		else cout << s1[i/2];
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:42:28: error: unable to find numeric literal operator 'operator""n'
   42 |         for(int i = 0; i < 2n; i++){
      |                            ^~
Language: C++

#include <bits/stdc++.h> 
using namespace std;
#define llu long long unsigned 
int main() 
{  
    string s1, s2;
  cin>>s1>>s2;
  for(int i=0; i<s1.length()&&i<s2.length();i++)
  {
    cout<<s1[i]<<s2[i];
  }
  if(i==s1.length())
  {
    for(;i<s2.length();i++)
      cout<<s2[i];
  }
  else
  {
    for(;i<s1.length();i++)
      cout<<s1[i];
  }
    return 0; 
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:12:6: error: 'i' was not declared in this scope
   12 |   if(i==s1.length())
      |      ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int N;
  String S,T;
  cin >> N;
  cin >> S >> T;
  for(int i=0;i<N;i++){
	cout << S.at(i);
    cout << T.at(i);
  }
  
  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,T;
      |   ^~~~~~
a.cc:8:10: error: 'S' was not declared in this scope
    8 |   cin >> S >> T;
      |          ^
a.cc:8:15: error: 'T' was not declared in this scope
    8 |   cin >> S >> T;
      |               ^
Language: C++

include <algorithm>
#include <array>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <string>
#include <utility>
#include <vector>

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;

int main() {
  int N;
  string S, T;

  cin >> N >> S >> T;

  rep(i, N) {
    cout << S[i] << T[i];
  }
  cout << endl;

  return 0;
}


Compiler output:
a.cc:1:1: error: 'include' does not name a type
    1 | include <algorithm>
      | ^~~~~~~
In file included from /usr/include/c++/14/array:39,
                 from a.cc:2:
/usr/include/c++/14/initializer_list:51:15: error: 'size_t' does not name a type
   51 |       typedef size_t            size_type;
      |               ^~~~~~
/usr/include/c++/14/initializer_list:1:1: note: 'size_t' is defined in header '<cstddef>'; this is probably fixable by adding '#include <cstddef>'
  +++ |+#include <cstddef>
    1 | // std::initializer_list support -*- C++ -*-
/usr/include/c++/14/initializer_list:57:7: error: 'size_type' does not name a type
   57 |       size_type                 _M_len;
      |       ^~~~~~~~~
/usr/include/c++/14/initializer_list:60:54: error: 'size_type' has not been declared
   60 |       constexpr initializer_list(const_iterator __a, size_type __l)
      |                                                      ^~~~~~~~~
/usr/include/c++/14/initializer_list:68:17: error: 'size_type' does not name a type
   68 |       constexpr size_type
      |                 ^~~~~~~~~
/usr/include/c++/14/initializer_list:45:11: fatal error: definition of 'class std::initializer_list<_E>' does not match '#include <initializer_list>'
   45 |     class initializer_list
      |           ^~~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
using namespace std ;
typedef long long ll ;
const int maxn = 205 ;
int n ;
char s[maxn] , t[maxn] ;
int main()
{
	scanf("%d" , &n) ;
	scanf("%s%s" , s , t) ;
	for(int i = 0 ; i < n ; i ++)
	  printf("%c%c" , s[i] , t[i]) ;
	printf("\n") ;
    return 0 ;`
}

Compiler output:
a.cc:14:15: error: stray '`' in program
   14 |     return 0 ;`
      |               ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
 
int main() {
    int n;
    string a,b;
    cin>>n>>a>>b;
    for(i=0;i<n;i++){
        cout<<a[i]<<b[i];
    }
    cout<<endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:9: error: 'i' was not declared in this scope
   10 |     for(i=0;i<n;i++){
      |         ^
Language: C++

#include<bits/stdc++.h>
using namespace std  ;
typedef long  long ll ;
#define pb push_back
ll a[5] ;
int main() {
    ll i,n  ;
    string s , t ;

    cin >> n>> s >> t ;
    a[n]++ , a[t]++ ;

    for(i=0;i<n;i++){
        cout << s[i] << t[i] ;
    }
    
    cout << endl ;




    return  0 ;
}






Compiler output:
a.cc: In function 'int main()':
a.cc:11:15: error: no match for 'operator[]' (operand types are 'll [5]' {aka 'long long int [5]'} and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   11 |     a[n]++ , a[t]++ ;
      |               ^
Language: C++

#include<bits/stdc++.h>
#define endl "\n"
#define pb push_back
#define ll long long
#define d1(x)  cerr << #x << "--> " << x << endl
#define d2(x, y)  cerr << #x << "--> " << x << " | " << #y << "--> " << y <<endl
#define d3(x, y,z)  cerr << #x << "--> " << x << " | " << #y << "--> " << y <<" | " << #z << "--> "<< z<< endl
#define vpll vector<pair<ll,ll>>
#define F first
#define S second
#define T ll tt; cin>>tt; while(tt--)
using namespace std;

ll mode=pow(10,9)+7;
bool cmp(pair<ll,ll> x, pair<ll, ll> y){
    return x.S<y.S;
}
//ll n,k,m;
bool check2(string ans, string s){
	for (int i=0;i<n;i++){
		ll aa=s[i];
		ll bb=ans[i];
		if (aa>bb) return false;
	}
	return true;
}

int main(){ 
    
  //  #ifndef ONLINE_JUDGE
//    freopen("input.txt", "r", stdin);
  //  #endif
    
    ios::sync_with_stdio(0);
    cin.tie(0);
	
	ll n;
	cin>>n;
	string a,b;
	cin>>a>>b;
	for (int i=0;i<n;i++){
		cout<<a[i]<<b[i];
	}
	
    return 0;
}

Compiler output:
a.cc: In function 'bool check2(std::string, std::string)':
a.cc:20:24: error: 'n' was not declared in this scope
   20 |         for (int i=0;i<n;i++){
      |                        ^
Language: C++

#include <bits/stdc++.h> 
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<ll> vl;
typedef pair<ll,ll> pll;
typedef vector<char> vc;
typedef map<long long,long long> mpi;
#define vbi vector<bool> 
#define mod 1000000007
#define all(x) x.begin(),x.end()
#define alr(x) x.rbegin(),x.rend()
#define mp make_pair
#define pb push_back
#define sd second
#define ft first
#define endl '\n'
#define cnl cout<<endl;
#define frr(i,b) for(ll i=0; i<b;i++)
#define fb(i,b) for(ll i=b-1; i>=0; i--)
#define pi  3.141592653589793238
#define ms(x,v) memset(x,v,sizeof(x))
#define MS0(X) memset((X), 0, sizeof((X)))
#define MS1(X) memset((X), -1, sizeof((X)))
#define deb(x) cout<<#x<<" = "<<x<<"\n";
#define CASET int ___T; scanf("%d", &___T); for(int cs=1;cs<=___T;cs++)
const int N = 2e5 + 5;
ll i,j,k;
void solve()

{
  ll n ;cin>>n;
 string s,t; cin>>s>>t;
 for(i=0;i<n;i++){
  cout<<s[i]<<<t[i];
 }

 return ; 
 
}
signed main(){
   
 //CASET
         solve();
  

 
    return 0;
}



Compiler output:
a.cc: In function 'void solve()':
a.cc:35:15: error: expected primary-expression before '<' token
   35 |   cout<<s[i]<<<t[i];
      |               ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define int long long
#define pb push_back
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define inp(n) for(i=0;i<n;i++) cin>>A[i];
#define inz(A) memset(A,0,sizeof(A))
#define lb lower_bound
#define ub upper_bound
#define all(v) v.begin(),v.end()
#define T 1000000
#define F first
#define S second
#define pi pair<int,int>
#define vi vector<int>
#define mii map<int,int>
#define vp vector<pair< int,int> >
#define mpi map<pair<int,int> ,int>
#define mip map<int, pair<int,int> >
#define inf INT_MAX
#define inf1 LONGLONG_MAX
#define sz(v) v.size()
#define rep(i,n) for(int i=0;i<n;i++)
#define forn(i,a,b) for(int i=a;i<=b;i++)
#define deb(x) cout<<#x<<"is "<<x<<endl;
#define lower(s) transform(all(s),s.begin(),::tolower)
#define endl "\n"
vector<int>adj [T];
			/*brownsands IIITA*/

void solve()
{	string s,s1;
 	int n,i;
	cin>>n;
  	cin>>s>>s1;
  for(i=0;i<n;i++)
  {
    cout<<s[i]<<s1[i];
}
signed main()
{
   boost
        int test=0,t;
		//cin>>t;
		t=1;
		while(test++ <t){
            //cout<<"Case "<<test<<": ";
            solve();
            //cerr << "\nTime : " << (double)clock() / (double)CLOCKS_PER_SEC << "s\n";
               }		
} 
               
			
 

				
		
		




Compiler output:
a.cc: In function 'void solve()':
a.cc:41:12: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   41 | signed main()
      |            ^~
a.cc:41:12: note: remove parentheses to default-initialize a variable
   41 | signed main()
      |            ^~
      |            --
a.cc:41:12: note: or replace parentheses with braces to value-initialize a variable
a.cc:42:1: error: a function-definition is not allowed here before '{' token
   42 | {
      | ^
a.cc:52:2: error: expected '}' at end of input
   52 | }
      |  ^
a.cc:33:1: note: to match this '{'
   33 | {       string s,s1;
      | ^
Language: C++

#include <bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < (int)n; i++)
#define all(x) (x).begin(),(x).end()
typedef long long int ll;
using namespace std;
int main()
{
  int a;
  cin >> a;
  string s, t;
  cin >> s >> t;
  string nes = s + t;
  REP(i, n){
    nes[2*i] = s[i];
    nes[2*i + 1] = t[i];
  }
  cout << nes << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:13:10: error: 'n' was not declared in this scope
   13 |   REP(i, n){
      |          ^
a.cc:2:44: note: in definition of macro 'REP'
    2 | #define REP(i, n) for (int i = 0; i < (int)n; i++)
      |                                            ^
Language: C++

#include <bits/stdc++.h> 
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<ll> vl;
typedef pair<ll,ll> pll;
typedef vector<char> vc;
typedef map<long long,long long> mpi;
#define vbi vector<bool> 
#define mod 1000000007
#define all(x) x.begin(),x.end()
#define alr(x) x.rbegin(),x.rend()
#define mp make_pair
#define pb push_back
#define sd second
#define ft first
#define endl '\n'
#define cnl cout<<endl;
#define frr(i,b) for(ll i=0; i<b;i++)
#define fb(i,b) for(ll i=b-1; i>=0; i--)
#define pi  3.141592653589793238
#define ms(x,v) memset(x,v,sizeof(x))
#define MS0(X) memset((X), 0, sizeof((X)))
#define MS1(X) memset((X), -1, sizeof((X)))
#define deb(x) cout<<#x<<" = "<<x<<"\n";
#define CASET int ___T; scanf("%d", &___T); for(int cs=1;cs<=___T;cs++)
const int N = 2e5 + 5;
ll i,j,k;
void solve()

{
  ll n ;cin>>n;
 stringn s,t; cin>>s>>t;
 for(i=0;i<n;i++){
  cout<<s[i]<<<t[i];
 }

 return ; 
 
}
signed main(){
  
 //CASET
         solve();
  

 
    return 0;
}



Compiler output:
a.cc: In function 'void solve()':
a.cc:33:2: error: 'stringn' was not declared in this scope
   33 |  stringn s,t; cin>>s>>t;
      |  ^~~~~~~
a.cc:33:20: error: 's' was not declared in this scope
   33 |  stringn s,t; cin>>s>>t;
      |                    ^
a.cc:33:23: error: 't' was not declared in this scope
   33 |  stringn s,t; cin>>s>>t;
      |                       ^
a.cc:35:15: error: expected primary-expression before '<' token
   35 |   cout<<s[i]<<<t[i];
      |               ^
Language: C

# coding: utf-8
# submission # - User: herp_sy
# https://atcoder.jp/contests/
#
# lang: Python3 (3.4.3)

import math
import statistics
import numpy as np
import queue

n = int(input())
s,t = map(str, input().split(' '))
for i in range(n):
  print(s[i], end = '')
  print(t[i], end = '')
print('')


Compiler output:
main.c:1:3: error: invalid preprocessing directive #coding
    1 | # coding: utf-8
      |   ^~~~~~
main.c:2:3: error: invalid preprocessing directive #submission
    2 | # submission # - User: herp_sy
      |   ^~~~~~~~~~
main.c:3:3: error: invalid preprocessing directive #https
    3 | # https://atcoder.jp/contests/
      |   ^~~~~
main.c:5:3: error: invalid preprocessing directive #lang
    5 | # lang: Python3 (3.4.3)
      |   ^~~~
main.c:7:1: error: unknown type name 'import'
    7 | import math
      | ^~~~~~
main.c:8:1: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'import'
    8 | import statistics
      | ^~~~~~
main.c:8:1: error: unknown type name 'import'
main.c:15:21: error: empty character constant
   15 |   print(s[i], end = '')
      |                     ^~
main.c:16:21: error: empty character constant
   16 |   print(t[i], end = '')
      |                     ^~
main.c:17:7: error: empty character constant
   17 | print('')
      |       ^~
Language: C++

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
using namespace std;
ll mod=1e9+7,i,j;
ll n;
ll a[300005];
string x,y
int main(){
    cin>>x>>y;
    for(i=0;i<x.size();i++){
        cout<<x[i]<<y[i];
    }
    return 0;
}



Compiler output:
a.cc:9:1: error: expected initializer before 'int'
    9 | int main(){
      | ^~~