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

int main(void)
{
    
    int m,f,r;
    
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if (m+f >= 80) {
            printf("A\n");
        }else if(m+f >= 65) {
            printf("B\n");
        }else if(m+f >= 50 ){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else{
                printf("D\n");
            }
        }else{
            printf("F\n");
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'scanf' was not declared in this scope
    7 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("A\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:14:13: error: 'printf' was not declared in this scope
   14 |             printf("B\n");
      |             ^~~~~~
a.cc:14:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:16:13: error: 'printf' was not declared in this scope
   16 |             printf("C\n");
      |             ^~~~~~
a.cc:16:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:19:17: error: 'printf' was not declared in this scope
   19 |                 printf("C\n");
      |                 ^~~~~~
a.cc:19:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:21:17: error: 'printf' was not declared in this scope
   21 |                 printf("D\n");
      |                 ^~~~~~
a.cc:21:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:24:13: error: 'printf' was not declared in this scope
   24 |             printf("F\n");
      |             ^~~~~~
a.cc:24:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    
    int m,f,r;
    
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if (m+f < 30) {
            printf("F\n");
        }else if(m+f < 50) {
            if (r >= 50) {
                printf("C\n");
            }else{
                printf("D\n");
            }
        }else if(m+f < 65 ){
            printf("B\n");
        }else if(m+f < 80){
            printf("A\n");
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'scanf' was not declared in this scope
    7 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("F\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:15:17: error: 'printf' was not declared in this scope
   15 |                 printf("C\n");
      |                 ^~~~~~
a.cc:15:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:17:17: error: 'printf' was not declared in this scope
   17 |                 printf("D\n");
      |                 ^~~~~~
a.cc:17:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:13: error: 'printf' was not declared in this scope
   20 |             printf("B\n");
      |             ^~~~~~
a.cc:20:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:22:13: error: 'printf' was not declared in this scope
   22 |             printf("A\n");
      |             ^~~~~~
a.cc:22:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    
    int m,f,r;
    
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if (m+f < 30) {
            printf("F\n");
        }else if(m+f < 50) {
            if (r >= 50) {
                printf("C\n");
            }else{
                printf("D\n");
            }
        }else if(m+f < 65 ){
            printf("B\n");
        }else if(m+f > 80){
            printf("A\n");
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'scanf' was not declared in this scope
    7 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("F\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:15:17: error: 'printf' was not declared in this scope
   15 |                 printf("C\n");
      |                 ^~~~~~
a.cc:15:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:17:17: error: 'printf' was not declared in this scope
   17 |                 printf("D\n");
      |                 ^~~~~~
a.cc:17:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:13: error: 'printf' was not declared in this scope
   20 |             printf("B\n");
      |             ^~~~~~
a.cc:20:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:22:13: error: 'printf' was not declared in this scope
   22 |             printf("A\n");
      |             ^~~~~~
a.cc:22:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    
    int m,f,r;
    
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if(m+f > 80){
            printf("A\n");
        }else if(m+f > 65){
            printf("B\n");
        }else if(m+f > 50){
            printf("C\n");
        }else if(m+f > 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else if(m+f > 0){
            printf("F\n");
        }else if(m+f+r == -3){
            break;
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:7:9: error: 'scanf' was not declared in this scope
    7 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("A\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:14:13: error: 'printf' was not declared in this scope
   14 |             printf("B\n");
      |             ^~~~~~
a.cc:14:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:16:13: error: 'printf' was not declared in this scope
   16 |             printf("C\n");
      |             ^~~~~~
a.cc:16:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:19:17: error: 'printf' was not declared in this scope
   19 |                 printf("C\n");
      |                 ^~~~~~
a.cc:19:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:21:17: error: 'printf' was not declared in this scope
   21 |                 printf("D\n");
      |                 ^~~~~~
a.cc:21:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:24:13: error: 'printf' was not declared in this scope
   24 |             printf("F\n");
      |             ^~~~~~
a.cc:24:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    int m,f,r;
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if(m+f >= 80){
            printf("A\n");
        }else if(m+f >= 65){
            printf("B\n");
        }else if(m+f >= 50){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else if(m+f > 0){
            printf("F\n");
        }else if(m+f+r == -3){
            break;
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:9: error: 'scanf' was not declared in this scope
    5 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:10:13: error: 'printf' was not declared in this scope
   10 |             printf("A\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("B\n");
      |             ^~~~~~
a.cc:12:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:14:13: error: 'printf' was not declared in this scope
   14 |             printf("C\n");
      |             ^~~~~~
a.cc:14:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:17:17: error: 'printf' was not declared in this scope
   17 |                 printf("C\n");
      |                 ^~~~~~
a.cc:17:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:19:17: error: 'printf' was not declared in this scope
   19 |                 printf("D\n");
      |                 ^~~~~~
a.cc:19:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:22:13: error: 'printf' was not declared in this scope
   22 |             printf("F\n");
      |             ^~~~~~
a.cc:22:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    int m,f,r;
    while (1) {
        scanf("%d %d %d\n",&m,&f,&r);
        
        if (m+f+r == -3) {
            break;
        }else if(m+f >= 80){
            printf("A\n");
        }else if(m+f >= 65){
            printf("B\n");
        }else if(m+f >= 50){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else if(m+f > 0){
            printf("F\n");
        }else if(m+f+r == -3){
            break;
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:9: error: 'scanf' was not declared in this scope
    5 |         scanf("%d %d %d\n",&m,&f,&r);
      |         ^~~~~
a.cc:10:13: error: 'printf' was not declared in this scope
   10 |             printf("A\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("B\n");
      |             ^~~~~~
a.cc:12:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:14:13: error: 'printf' was not declared in this scope
   14 |             printf("C\n");
      |             ^~~~~~
a.cc:14:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:17:17: error: 'printf' was not declared in this scope
   17 |                 printf("C\n");
      |                 ^~~~~~
a.cc:17:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:19:17: error: 'printf' was not declared in this scope
   19 |                 printf("D\n");
      |                 ^~~~~~
a.cc:19:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:22:13: error: 'printf' was not declared in this scope
   22 |             printf("F\n");
      |             ^~~~~~
a.cc:22:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    int m,f,r;
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        
        if(m+f >= 80){
            printf("A\n");
        }else if(m+f >= 65){
            printf("B\n");
        }else if(m+f >= 50){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else if(m+f > 0){
            printf("F\n");
        }else if(m+f+r == -3){
            break;
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:9: error: 'scanf' was not declared in this scope
    5 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:8:13: error: 'printf' was not declared in this scope
    8 |             printf("A\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:10:13: error: 'printf' was not declared in this scope
   10 |             printf("B\n");
      |             ^~~~~~
a.cc:10:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:12:13: error: 'printf' was not declared in this scope
   12 |             printf("C\n");
      |             ^~~~~~
a.cc:12:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:15:17: error: 'printf' was not declared in this scope
   15 |                 printf("C\n");
      |                 ^~~~~~
a.cc:15:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:17:17: error: 'printf' was not declared in this scope
   17 |                 printf("D\n");
      |                 ^~~~~~
a.cc:17:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:13: error: 'printf' was not declared in this scope
   20 |             printf("F\n");
      |             ^~~~~~
a.cc:20:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    int m,f,r;
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        if (m == -1 || f == -1) {
            printf("F\n");
        }else if(m+f >= 80){
            printf("A\n");
        }else if(m+f >= 65){
            printf("B\n");
        }else if(m+f >= 50){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else if(m+f > 0){
            printf("F\n");
        }else if(m == -1 && f == -1 && r == -1){
            break;
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:9: error: 'scanf' was not declared in this scope
    5 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:7:13: error: 'printf' was not declared in this scope
    7 |             printf("F\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:9:13: error: 'printf' was not declared in this scope
    9 |             printf("A\n");
      |             ^~~~~~
a.cc:9:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:11:13: error: 'printf' was not declared in this scope
   11 |             printf("B\n");
      |             ^~~~~~
a.cc:11:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:13:13: error: 'printf' was not declared in this scope
   13 |             printf("C\n");
      |             ^~~~~~
a.cc:13:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:16:17: error: 'printf' was not declared in this scope
   16 |                 printf("C\n");
      |                 ^~~~~~
a.cc:16:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:18:17: error: 'printf' was not declared in this scope
   18 |                 printf("D\n");
      |                 ^~~~~~
a.cc:18:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:21:13: error: 'printf' was not declared in this scope
   21 |             printf("F\n");
      |             ^~~~~~
a.cc:21:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

int main(void)
{
    int m,f,r;
    while (1) {
        scanf("%d %d %d",&m,&f,&r);
        if(m == -1 && f == -1 && r == -1){
            break;
        }else if (m == -1 || f == -1) {
            printf("F\n");
        }else if(m+f >= 80){
            printf("A\n");
        }else if(m+f >= 65){
            printf("B\n");
        }else if(m+f >= 50){
            printf("C\n");
        }else if(m+f >= 30){
            if (r >= 50) {
                printf("C\n");
            }else {
                printf("D\n");
            }
        }else{
            printf("F\n");
        }
    }
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:5:9: error: 'scanf' was not declared in this scope
    5 |         scanf("%d %d %d",&m,&f,&r);
      |         ^~~~~
a.cc:9:13: error: 'printf' was not declared in this scope
    9 |             printf("F\n");
      |             ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | int main(void)
a.cc:11:13: error: 'printf' was not declared in this scope
   11 |             printf("A\n");
      |             ^~~~~~
a.cc:11:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:13:13: error: 'printf' was not declared in this scope
   13 |             printf("B\n");
      |             ^~~~~~
a.cc:13:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:15:13: error: 'printf' was not declared in this scope
   15 |             printf("C\n");
      |             ^~~~~~
a.cc:15:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:18:17: error: 'printf' was not declared in this scope
   18 |                 printf("C\n");
      |                 ^~~~~~
a.cc:18:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:17: error: 'printf' was not declared in this scope
   20 |                 printf("D\n");
      |                 ^~~~~~
a.cc:20:17: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:23:13: error: 'printf' was not declared in this scope
   23 |             printf("F\n");
      |             ^~~~~~
a.cc:23:13: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

#include<iostream>
using namespace std;
int main(){
	int tyukan,kimatu,saitest,matome;
	while(1){
		cin>> tyukan >> kimatu >> saitest;
		if(tyukan==-1&&kimatu==-1&&saitest==-1) break;

		matome=tyukan+kimatu;

		if(matome>=80){
			
			
			cout<<'A'<<"\n";
		}else if(matome>=65){
			
			
			cout<<'B'<<"\n";
		}else if(matome>=50){
			
			
			cout<<'C'<<"\n";
		}else if(matome>=30){
			if(saitest>=50){

				cout<<'C'<<\n;
			
			}else if(saitest<50){

			cout<<'D'<<"\n";
			}}else{
			
			
			cout<<'F'<<"\n";
		}
		}
			
	
	return 0;
}

Compiler output:
a.cc:26:44: error: stray '\' in program
   26 |                                 cout<<'C'<<\n;
      |                                            ^
a.cc: In function 'int main()':
a.cc:26:45: error: 'n' was not declared in this scope
   26 |                                 cout<<'C'<<\n;
      |                                             ^
Language: C++

#include<iostream>
using namespace std;
int main(){
	int tyukan,kimatu,saitest,matome;
	while(1){
		while(1){
		cin>> tyukan >> kimatu >> saitest;
		if(tyukan<=50&&kimatu<=50&&saitest<=100) break;
		}if(tyukan==-1&&kimatu==-1&&saitest==-1) break;
		if(saitest==-1){
			matome=tyukan+kimatu-1;
		}else{
			matome=tukan+kimatu;
		}
		if(tyukan==-1||kimatu==-1){
			cout<<"F";
		}

		if(matome>=80){
			
			
			cout<<'A'<<"\n";
		}else if(matome>=65){
			
			
			cout<<'B'<<"\n";
		}else if(matome>=50){
			
			
			cout<<'C'<<"\n";
		}else if(matome>=30){
			if(saitest>=50){

				cout<<'C'<<"\n";
			
			}else if(saitest<50){

			cout<<'D'<<"\n";
			}}else{
			
			
			cout<<'F'<<"\n";
		}
		}
			
	
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:32: error: 'tukan' was not declared in this scope; did you mean 'tyukan'?
   13 |                         matome=tukan+kimatu;
      |                                ^~~~~
      |                                tyukan
Language: C++

#include <stdio.h>

static const int ABSENCE = -1;

char JudgeGrade(int mid, int final, int retest) {
	if ((mid == ABSENCE) || (final == ABSENCE)) {
		return 'F';
	}
	int sum = mid + final;
	if (sum >= 80) {
		return 'A';
	}
	if (sum >= 65) {
		return 'B';
	}
	if (sum >= 50) {
		return 'C';
	}
	if (sum >= 30) {
		return (r >= 50) ? 'C' : 'D';
	}
	return 'F';
}

int main(void) {
	int m = 0, f = 0, r = 0;
	
	for (;;) {
		scanf("%d %d %d", &m, &f, &r);
		if ((m == -1) && (f == -1) && (r == -1)) {
			break;
		}
		printf("%c\n", JudgeGrade(m, f, r));
	}
	return 0;
}

Compiler output:
a.cc: In function 'char JudgeGrade(int, int, int)':
a.cc:20:25: error: 'r' was not declared in this scope
   20 |                 return (r >= 50) ? 'C' : 'D';
      |                         ^
Language: Java

import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int alfa = 32;
		String line, ans; char[] lineC;
		
		while(true){
			ans = "";
			line = in.nextLine();
			lineC = line.toCharArray();
			
			for(int i=0;i<lineC.length;i++){
				if(Character.isUpperCase(lineC[i])){
					ans += (char)(lineC[i] + alfa);
				else if(Character.isLowerCase(lineC[i]))
					ans += (char)(lineC[i] - alfa);
				else ans += lineC[i];
			}
			
			System.out.println(ans);
		}
	}

}

Compiler output:
Main.java:18: error: 'else' without 'if'
				else if(Character.isLowerCase(lineC[i]))
				^
Main.java:27: error: reached end of file while parsing
}
 ^
2 errors
Language: Java

import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    while (true) {
      String str = sc.next();
      if (str == \n) {
        break;
      }
      char ch[] = str.toCharArray();
      for (int idx = 0; idx < str.length(); idx++) {
        if (Character.isUpperCase(ch[idx])) {
          ch[idx] = Character.isLowerCase(ch[idx]);
        }
        else if (Character.isLowerCase(ch[idx])) {
          ch[idx] = Character.isUpperCase(ch[idx]);
        }
      }
      for (int idx = 0; idx < str.length(); idx++) {
        System.out.print(ch[idx]);
      }
      System.out.print(" ");
    }
  }
}

Compiler output:
Main.java:7: error: illegal character: '\'
      if (str == \n) {
                 ^
Main.java:7: error: not a statement
      if (str == \n) {
                  ^
Main.java:7: error: ';' expected
      if (str == \n) {
                   ^
3 errors
Language: Java

import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    while (true) {
      String str = sc.next();
      if (str.equals("\n")) {
        break;
      }
      char ch[] = str.toCharArray();
      for (int idx = 0; idx < str.length(); idx++) {
        if (Character.isUpperCase(ch[idx])) {
          ch[idx] = Character.isLowerCase(ch[idx]);
        }
        else if (Character.isLowerCase(ch[idx])) {
          ch[idx] = Character.isUpperCase(ch[idx]);
        }
      }
      for (int idx = 0; idx < str.length(); idx++) {
        System.out.print(ch[idx]);
      }
      System.out.print(" ");
    }
  }
}

Compiler output:
Main.java:13: error: incompatible types: boolean cannot be converted to char
          ch[idx] = Character.isLowerCase(ch[idx]);
                                         ^
Main.java:16: error: incompatible types: boolean cannot be converted to char
          ch[idx] = Character.isUpperCase(ch[idx]);
                                         ^
2 errors
Language: Java

import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String str = sc.nextLine();
    for (int i = 0; i < str.length(); i++) {
      char ch = str.charAt(i);
      if (Character.isUpperCase(ch)) {
        ch[idx] = Character.toLowerCase(ch);
      }
      else if (Character.isLowerCase(ch)) {
        ch[idx] = Character.toUpperCase(ch);
      }
      System.out.print(ch);
    }
  }
}

Compiler output:
Main.java:9: error: cannot find symbol
        ch[idx] = Character.toLowerCase(ch);
           ^
  symbol:   variable idx
  location: class Main
Main.java:9: error: array required, but char found
        ch[idx] = Character.toLowerCase(ch);
          ^
Main.java:12: error: cannot find symbol
        ch[idx] = Character.toUpperCase(ch);
           ^
  symbol:   variable idx
  location: class Main
Main.java:12: error: array required, but char found
        ch[idx] = Character.toUpperCase(ch);
          ^
4 errors
Language: Java

import java.util.Scanner;
public class　Main {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		String s=sc.next();
		char t[]=s.toCharArray();
		boolean[] b=new boolean[s.length()];
		for(int i=0;i<s.length();i++){
			if(Character.isUpperCase(t[i]))b[i]=true;
			else if(Character.isLowerCase(t[i]))b[i]=false;
		}
		
		for(int i=0;i<s.length();i++){
			if(b[i]==false)System.out.print(Character.toUpperCase(t[i]));
			else if(b[i]==true)System.out.print(Character.toLowerCase(t[i]));
		}
		System.out.printf("\n");
		sc.close();
		System.exit(0);
	}

}

Compiler output:
Main.java:2: error: illegal character: '\u3000'
public class?Main {
            ^
1 error
Language: Java

public class p10018 {
	public static void main(String args[]) {
		varying();
	}

	static void varying() {

		String word;
		BufferedReader input = new BufferedReader(new InputStreamReader(
				System.in));
		try {
			word = input.readLine();

			for (int i = 0; i < word.length(); i++) {
				char c = word.charAt(i);
				if (Character.isUpperCase(c)) {
					System.out.print(Character.toLowerCase(c));
				} else if (Character.isLowerCase(c)) {
					System.out.print(Character.toUpperCase(c));
				} else {
					System.out.print(c);
				}
			}

		} catch (IOException e) {

		}

	}

}

Compiler output:
Main.java:1: error: class p10018 is public, should be declared in a file named p10018.java
public class p10018 {
       ^
Main.java:9: error: cannot find symbol
		BufferedReader input = new BufferedReader(new InputStreamReader(
		^
  symbol:   class BufferedReader
  location: class p10018
Main.java:9: error: cannot find symbol
		BufferedReader input = new BufferedReader(new InputStreamReader(
		                           ^
  symbol:   class BufferedReader
  location: class p10018
Main.java:9: error: cannot find symbol
		BufferedReader input = new BufferedReader(new InputStreamReader(
		                                              ^
  symbol:   class InputStreamReader
  location: class p10018
Main.java:25: error: cannot find symbol
		} catch (IOException e) {
		         ^
  symbol:   class IOException
  location: class p10018
5 errors
Language: Java

import java.io.*;

public class p10018 {
	public static void main(String args[]) {
		varying();
	}

	static void varying() {

		String word;
		BufferedReader input = new BufferedReader(new InputStreamReader(
				System.in));
		try {
			word = input.readLine();

			for (int i = 0; i < word.length(); i++) {
				char c = word.charAt(i);
				if (Character.isUpperCase(c)) {
					System.out.print(Character.toLowerCase(c));
				} else if (Character.isLowerCase(c)) {
					System.out.print(Character.toUpperCase(c));
				} else {
					System.out.print(c);
				}
			}

		} catch (IOException e) {

		}

	}

}

Compiler output:
Main.java:3: error: class p10018 is public, should be declared in a file named p10018.java
public class p10018 {
       ^
1 error
Language: Java

import java.io.*;

class p10018 {
	public static void main(String args[]) {
//		varying();
		
		String word;
		BufferedReader input = new BufferedReader(new InputStreamReader(
				System.in));
		try {

			word = input.readLine();

			for (int i = 0; i < word.length(); i++) {
				char c = word.charAt(i);
				if (Character.isUpperCase(c)) {
					System.out.print(Character.toLowerCase(c));
				} else if (Character.isLowerCase(c)) {
					System.out.print(Character.toUpperCase(c));
				} else {
					System.out.print(c);
				}
			}

		} catch (IOException e) {

		}
		return;

	}class p10018 {
	public static void main(String args[]) {
//		varying();
		
		String word;
		BufferedReader input = new BufferedReader(new InputStreamReader(
				System.in));
		try {

			word = input.readLine();

			for (int i = 0; i < word.length(); i++) {
				char c = word.charAt(i);
				if (Character.isUpperCase(c)) {
					System.out.print(Character.toLowerCase(c));
				} else if (Character.isLowerCase(c)) {
					System.out.print(Character.toUpperCase(c));
				} else {
					System.out.print(c);
				}
			}

		} catch (IOException e) {

		}
		return;

	}
}

Compiler output:
Main.java:58: error: reached end of file while parsing
}
 ^
1 error
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i=0;i<1200;i++){
    if((x[i]<=90) && (x[i]>=65)){
      x[i]=x[i]+32;
    }
    else if((x[i]>=97) && (x[i]<=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s\n",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |          ^
main.c:7:24: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |                        ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |               ^
main.c:10:29: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |                             ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i =0;i <1200;i++){
    if((x[i] <=90) && (x[i] >=65)){
      x[i]=x[i]+32;
    }
    else if((x[i] >=97) && (x[i] <=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s\n",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) && (x[i] >=65)){
      |          ^
main.c:7:25: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) && (x[i] >=65)){
      |                         ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) && (x[i] <=122)){
      |               ^
main.c:10:30: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) && (x[i] <=122)){
      |                              ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i=0;i<1200;i++){
    if((x[i]<=90) && (x[i]>=65)){
      x[i]=x[i]+32;
    }
    else if((x[i]>=97) && (x[i]<=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |          ^
main.c:7:24: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |                        ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |               ^
main.c:10:29: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |                             ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i=0;i<x;i++){
    if((x[i]<=90) && (x[i]>=65)){
      x[i]=x[i]+32;
    }
    else if((x[i]>=97) && (x[i]<=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |          ^
main.c:7:24: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i]<=90) && (x[i]>=65)){
      |                        ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |               ^
main.c:10:29: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i]>=97) && (x[i]<=122)){
      |                             ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i =0;i <x;i++){
    if((x[i] <=90) && (x[i] >=65)){
      x[i]=x[i]+32;
    }
    else if((x[i] >=97) && (x[i] <=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) && (x[i] >=65)){
      |          ^
main.c:7:25: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) && (x[i] >=65)){
      |                         ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) && (x[i] <=122)){
      |               ^
main.c:10:30: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) && (x[i] <=122)){
      |                              ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i =0;i <x;i++){
    if((x[i] <=90) || (x[i] >=65)){
      x[i]=x[i]+32;
    }
    else if((x[i] >=97) || (x[i] <=122)){
      x[i]=x[i]-32;
    }
  }
  printf("%s",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) || (x[i] >=65)){
      |          ^
main.c:7:25: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) || (x[i] >=65)){
      |                         ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |        ^
main.c:8:13: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i]=x[i]+32;
      |             ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) || (x[i] <=122)){
      |               ^
main.c:10:30: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) || (x[i] <=122)){
      |                              ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |        ^
main.c:11:13: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i]=x[i]-32;
      |             ^
Language: C

#include<stdio.h>
int main(){
  char x;
  int i;
  scanf("%s",x);
  for(i =0;i <x;i++){
    if((x[i] <=90) || (x[i] >=65)){
      x[i] =x[i]+32;
    }
    else if((x[i] >=97) || (x[i] <=122)){
      x[i] =x[i]-32;
    }
  }
  printf("%s",x);
  return(0);
}  

Compiler output:
main.c: In function 'main':
main.c:7:10: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) || (x[i] >=65)){
      |          ^
main.c:7:25: error: subscripted value is neither array nor pointer nor vector
    7 |     if((x[i] <=90) || (x[i] >=65)){
      |                         ^
main.c:8:8: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i] =x[i]+32;
      |        ^
main.c:8:14: error: subscripted value is neither array nor pointer nor vector
    8 |       x[i] =x[i]+32;
      |              ^
main.c:10:15: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) || (x[i] <=122)){
      |               ^
main.c:10:30: error: subscripted value is neither array nor pointer nor vector
   10 |     else if((x[i] >=97) || (x[i] <=122)){
      |                              ^
main.c:11:8: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i] =x[i]-32;
      |        ^
main.c:11:14: error: subscripted value is neither array nor pointer nor vector
   11 |       x[i] =x[i]-32;
      |              ^
Language: C

#include<stdio.h>
#include<ctype.h>
void str_x(char s[]){
  int i=0;
  while(s[i]){
    if(s[i]>='a' && s[i]<='z'){
      s[i]=toupper(s[i]);
      i++;
    }
    else if(s[i]>='A' && s[i]<='Z'){
      s[i]=tolower(s[i]);
      i++;
    }
  }
}

int main(void){
  char str[1200];
    scanf("%s",str);

    str_x(str);
    printf("%s\n",str);
  }
  return 0;
}

Compiler output:
main.c:24:3: error: expected identifier or '(' before 'return'
   24 |   return 0;
      |   ^~~~~~
main.c:25:1: error: expected identifier or '(' before '}' token
   25 | }
      | ^
Language: C

#include<stdio.h>
#include<string.h>
#include<ctype.h>

int main(void){

  int n,i;
  char str[1000];

  gets(str);

  n=strlen(str);

  for(i=0;i<n;i++)
{
  if(isupper(str[i])!=0)str[i]=tolower(str[i]);
  else if(islower(str[i])!=0)str[i]=toupper(str[i]);
 }

  printf("%s\n",str);

  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:10:3: error: implicit declaration of function 'gets'; did you mean 'fgets'? [-Wimplicit-function-declaration]
   10 |   gets(str);
      |   ^~~~
      |   fgets
Language: C

#include <stdio.h>
#include <string.h>
int main(void){
char buff[256];
int i=0;
int len=0;
	gets(buff);
	len=strlen(buff);
	for (i=0;i<len;i++){
		if (64<buff[i] && buff[i]<91){
			buff[i]=buff[i]+32;
		} else if (96<buff[i] && buff[i]<123){
			buff[i]=buff[i]-32;
		}
	}
	for (i=0;i<len;i++){
		printf("%c", buff[i]);
	}
	printf("\n");
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:7:9: error: implicit declaration of function 'gets'; did you mean 'fgets'? [-Wimplicit-function-declaration]
    7 |         gets(buff);
      |         ^~~~
      |         fgets
Language: C

#include <stdio.h>

int main(void) {
    char s[100];
    int i;
    
    gets();
    
    for(i=0;i<=;i++){
        if(65 <= s[i] && s[i] <= 90) s[i] += 32;
        if(97 <= s[i] && s[i] <= 122) s[i] -= 32;
    }
    
    printf("%s", s);
    
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:7:5: error: implicit declaration of function 'gets'; did you mean 'fgets'? [-Wimplicit-function-declaration]
    7 |     gets();
      |     ^~~~
      |     fgets
main.c:9:16: error: expected expression before ';' token
    9 |     for(i=0;i<=;i++){
      |                ^
Language: C

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

int main()
{
	string str;

	while(getline(cin,str))
		for(int i=0; i<str.size(); i++){
			if(islower(str[i])) toupper(str[i]);
			else  tolower(str[i]);
		}
		cout << str << "\n";
	
	return 0;
}

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

#include<iostream>
#include<cstdio>
using namespace std;
 
int main(){
    string s;
	getline(cin,s);
	for(int i=0;i<s.size();i++){
		if(islower(s[i])){
			s[i]=toupper(s[i]);
		}else if(isupper(s[i])){
			s[i]=tolower(s[i]);
		}
	}
	cout<<s<<endl;
    return 0;
}

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

#include<stdio.h>
#include<conio.h>

int main()
{
	int i=0;
	char moji[1000];
	gets(moji);
	for(i=0;i<1000;i++){
		if(moji[i]>=65 && moji[i]<=90){        moji[i]+=32;
		}else if(moji[i]>=97 && moji[i]<=122){ moji[i]-=32;
		}
	}
	printf("%s\n",moji);
	return 0;
}

Compiler output:
main.c:2:9: fatal error: conio.h: No such file or directory
    2 | #include<conio.h>
      |         ^~~~~~~~~
compilation terminated.
Language: C

#include<stdio.h>

int main(void)
{
char line[1024];
gets(line);

int i;
char c;

while((c=line[i++])!='\0'){
if(c>='a' && c<='z'){ c += 'A'-'a'; }
else if(c>='A' && c<='Z'){ c += 'a'-'A'; }
}
putchar(c);
}

return 0;
}

Compiler output:
main.c: In function 'main':
main.c:6:1: error: implicit declaration of function 'gets'; did you mean 'fgets'? [-Wimplicit-function-declaration]
    6 | gets(line);
      | ^~~~
      | fgets
main.c: At top level:
main.c:18:1: error: expected identifier or '(' before 'return'
   18 | return 0;
      | ^~~~~~
main.c:19:1: error: expected identifier or '(' before '}' token
   19 | }
      | ^
Language: C

#include <stdio.h>
#include <ctype.h>

int main(void)
{
  char ch;
  char str;
  int i = 0;

  while(1) {
    scanf("%c", &ch);
    if (ch == '\n') break;

    if (islower(ch))
      toupper(ch);
    else if (isupper(ch))
      tolower(ch);

    str[i] = ch;
    i++;
  }
  printf("%s\n", str);

  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:19:8: error: subscripted value is neither array nor pointer nor vector
   19 |     str[i] = ch;
      |        ^
Language: C

#include <stdio.h>

main()
{
	char ch;
	while(1){
		scanf("%c", &ch);
		if(ch==','||ch==' '||ch'.'){
			printf("%c",ch);
		} else {
			if(islower(ch)) printf("%c", toupper(ch));
			if(isupper(ch)) printf("%c", tolower(ch));
		}
		if(ch=='\n') break;
	}
	return 0;
}

Compiler output:
main.c:3:1: error: return type defaults to 'int' [-Wimplicit-int]
    3 | main()
      | ^~~~
main.c: In function 'main':
main.c:8:40: error: expected ')' before '.'
    8 |                 if(ch==','||ch==' '||ch'.'){
      |                   ~                    ^~~
      |                                        )
main.c:11:28: error: implicit declaration of function 'islower' [-Wimplicit-function-declaration]
   11 |                         if(islower(ch)) printf("%c", toupper(ch));
      |                            ^~~~~~~
main.c:2:1: note: include '<ctype.h>' or provide a declaration of 'islower'
    1 | #include <stdio.h>
  +++ |+#include <ctype.h>
    2 | 
main.c:11:54: error: implicit declaration of function 'toupper' [-Wimplicit-function-declaration]
   11 |                         if(islower(ch)) printf("%c", toupper(ch));
      |                                                      ^~~~~~~
main.c:11:54: note: include '<ctype.h>' or provide a declaration of 'toupper'
main.c:12:28: error: implicit declaration of function 'isupper' [-Wimplicit-function-declaration]
   12 |                         if(isupper(ch)) printf("%c", tolower(ch));
      |                            ^~~~~~~
main.c:12:28: note: include '<ctype.h>' or provide a declaration of 'isupper'
main.c:12:54: error: implicit declaration of function 'tolower' [-Wimplicit-function-declaration]
   12 |                         if(isupper(ch)) printf("%c", tolower(ch));
      |                                                      ^~~~~~~
main.c:12:54: note: include '<ctype.h>' or provide a declaration of 'tolower'
Language: C

#include <stdio.h>
#include <conio.h>

int main(void)
{
	char c;
	
	while (1){
		scanf("%c", &c);
		
		if (c >= 'a' && c <= 'z'){
			c -= 0x20;
		}
		else if (c >= 'A' && c <= 'Z'){
			c += 0x20;
		}
		
		printf("%c", c);
		
		if (c == '\n'){
			break;
		}
	}
	
	return (0);
}

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

#include <stdio.h>
#include <iostream>
 
int main(){
  char c;
  while(1){
    scanf("%c",&c);
    if(c=='\n')
      break;
    else if(islower(c))
		printf("%c",toupper(c));
    else if(isupper(c)) 
		printf("%c",tolower(c));
    else 
		printf("%c",c);
  }
  return 0;
}

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