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

#include <stdio.h>
  int main(){
    int m,f,r;
     int i;
      for(i=0;i>=0;i++){
        scanf("%d%d%d",&m,&f,&r);
          if(m == -1 && f == -1 && r == -1){
            break;
              }
                if(m + f >= 80){
                 printf("%c\n" ,A);
                  }else if(m + f>=65){
                   printf("%c\n",B);
                    }else if(m+f>=50){
                      printf("%c\n",C);
                      }else if(m+f<30){
                       printf("%c\n",F);
                         }
      if(m =-1 || f = -1)
         printf("%c\n",F);
        if(m+f<50 && m+f>=30 && f>=50){
         printf("%c\n",C);
          }else if(m+f<50 && m+f>=30 && f<50){
           printf("%c\n",D);
           }
}
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:11:33: error: 'A' undeclared (first use in this function)
   11 |                  printf("%c\n" ,A);
      |                                 ^
main.c:11:33: note: each undeclared identifier is reported only once for each function it appears in
main.c:13:34: error: 'B' undeclared (first use in this function)
   13 |                    printf("%c\n",B);
      |                                  ^
main.c:15:37: error: 'C' undeclared (first use in this function)
   15 |                       printf("%c\n",C);
      |                                     ^
main.c:17:38: error: 'F' undeclared (first use in this function)
   17 |                        printf("%c\n",F);
      |                                      ^
main.c:19:21: error: lvalue required as left operand of assignment
   19 |       if(m =-1 || f = -1)
      |                     ^
main.c:24:26: error: 'D' undeclared (first use in this function)
   24 |            printf("%c\n",D);
      |                          ^
Language: C

#include <stdio.h>
  int main(){
    int m,f,r;
     int i;
      for(i=0;i>=0;i++){
        scanf("%d%d%d",&m,&f,&r);
          if(m == -1 && f == -1 && r == -1){
            break;
              }
                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){
                       printf("F\n");
                         }
      if(m =-1 || f = -1)
         printf("F\n");
        if(m+f<50 && m+f>=30 && f>=50){
         printf("C\n");
          }else if(m+f<50 && m+f>=30 && f<50){
           printf("D\n");
           }
}
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:19:21: error: lvalue required as left operand of assignment
   19 |       if(m =-1 || f = -1)
      |                     ^
Language: C

#include <stdio.h>
  int main(){
    int m,f,r;
     int i;
      for(i=0;i>=0;i++){
        scanf("%d%d%d",&m,&f,&r);
          if(m == -1 && f == -1 && r == -1){
            break;
              }
                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){
                       printf("F\n");
                         }
      if(m =-1 || f = -1){
         printf("F\n");}
        if(m+f<50 && m+f>=30 && f>=50){
         printf("C\n");
          }else if(m+f<50 && m+f>=30 && f<50){
           printf("D\n");
           }
}
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:19:21: error: lvalue required as left operand of assignment
   19 |       if(m =-1 || f = -1){
      |                     ^
Language: C

#include <stdio.h>
  int main(){
    int m,f,r;
     int i;
      for(i=0;i>=0;i++){
        scanf("%d%d%d",&m,&f,&r);
          if(m == -1 && f == -1 && r == -1){
            break;
              }
                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){
                       printf("F\n");
                         }
      if(m =-1 || f = -1){
         printf("F\n");
}
        if(m+f<50 && m+f>=30 && f>=50){
         printf("C\n");
          }else if(m+f<50 && m+f>=30 && f<50){
           printf("D\n");
           }
}
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:19:21: error: lvalue required as left operand of assignment
   19 |       if(m =-1 || f = -1){
      |                     ^
Language: C

#include<stdio.h>
int main(void)
{
	int m,f,r,i[100],j=0;
	while(1)
	{
		j=j+1;
		scanf("%d %d %d",&m,&f,&r);
		i[j]=m+f;
		if(i[j]+r==-3)
			break;
		if(i[j]>=80)
			i[j]=10;
		else if(i[j]>=65)
			i[j]=11;
		else if((i[j]>=50)||(r>=50))
			i[j]=12;
		else if(i[j]>=30)
			i[j]=13;
		else if((m==-1)||(f==-1))
			i[j]==15
		else 
			i[j]=15;
	}
	for(m=1;m<=j-1;m++)
	{
		printf("%X\n",i[m]);
	}
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:21:33: error: expected ';' before 'else'
   21 |                         i[j]==15
      |                                 ^
      |                                 ;
   22 |                 else
      |                 ~~~~
Language: C

#include<stdio.h>
main(){

  int m,f,r,x;

  while(1){

    scanf("%d %d %d",&m,&f,&r);
    x=m+f;

    if(m==-1 || f==-1){
      printf("F");
    }

    else if(m==-1 && f==-1 && r==-1){
      break;
    }

    else if(x>80){
      printf("A");
    }
    else if(65<=x && x<80){
      printf("B");
    }
    else if(50<=x && x<65 || r>=50){
      printf("C");
    }
    else if(30<=x && x<50){
      printf("D");
    }
    else if(x<30 || m==-1 || f==-1){
      printf("F");
    }

    printf("\n");

  }

Compiler output:
main.c:2:1: error: return type defaults to 'int' [-Wimplicit-int]
    2 | main(){
      | ^~~~
main.c: In function 'main':
main.c:37:3: error: expected declaration or statement at end of input
   37 |   }
      |   ^
Language: C

#include<stdio.h>
main(){

  int m,f,r,x;

  while(1){

    scanf("%d %d %d",&m,&f,&r);
    x=m+f;

    if(m==-1 && f==-1 && r==-1){
      break;
    }

    else if(m==-1 || f==-1){
      printf("F");
    }

    else if(80<x){
      printf("A");
    }
    else if(65<=x && x<80){
      printf("B");
    }
    else if(50<=x && x<65 || r>=50){
      printf("C");
    }
    else if(30<=x && x<50){
      printf("D");
    }
    else if(x<30 || m==-1 || f==-1){
      printf("F");
    }

    printf("\n");

  }

Compiler output:
main.c:2:1: error: return type defaults to 'int' [-Wimplicit-int]
    2 | main(){
      | ^~~~
main.c: In function 'main':
main.c:37:3: error: expected declaration or statement at end of input
   37 |   }
      |   ^
Language: C

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

Compiler output:
main.c: In function 'main':
main.c:25:3: error: expected declaration or statement at end of input
   25 |   return (0);
      |   ^~~~~~
Language: C

#include <stdio.h>

struct Math{
    int m;
    int f;
    int r;
}

int main()
{
    struct Math a[65535];
    int i,t,sum;
    
    for(i=0;;i++){
        scanf("%d %d %d",a[i].m,a[i].f,a[i].r);
        if(a[i].m==a[i].f==a[i].r==0){
            t=i;break;
        }
    }

    for(i=0;i<t;i++){
        sum=a[i].m+a[i].f;
        if(a[i].m==-1||a[i].f==-1||sum<30){
            printf("F\n");
        }else if(sum>=80){
            printf("A\n");
        }else if(sum>=65&&sum<80){
            printf("B\n");
        }else if(sum>=50&&sum<65){
            printf("C\n");
        }else if(sum>=30&&sum<50){
            if(a[i].r>=50){
                printf("C\n");
            }else{
                printf("D\n");
            }
        }
        
    

Compiler output:
main.c:9:1: error: expected ';', identifier or '(' before 'int'
    9 | int main()
      | ^~~
main.c: In function 'main':
main.c:37:9: error: expected declaration or statement at end of input
   37 |         }
      |         ^
main.c:37:9: error: expected declaration or statement at end of input
Language: C

#include <stdio.h>

struct Math{
    int m;
    int f;
    int r;
}

int main()
{
    struct Math a[65535];
    int i,t,sum;
    
    for(i=0;;i++){
        scanf("%d %d %d",a[i].m,a[i].f,a[i].r);
        if(a[i].m==a[i].f==a[i].r==0){
            t=i;break;
        }
    }

    for(i=0;i<t;i++){
        sum=a[i].m+a[i].f;
        if(a[i].m==-1||a[i].f==-1||sum<30){
            printf("F\n");
        }else if(sum>=80){
            printf("A\n");
        }else if(sum>=65&&sum<80){
            printf("B\n");
        }else if(sum>=50&&sum<65){
            printf("C\n");
        }else if(sum>=30&&sum<50){
            if(a[i].r>=50){
                printf("C\n");
            }else{
                printf("D\n");
            }
        }
    }
    return 0;
}

        
    

Compiler output:
main.c:9:1: error: expected ';', identifier or '(' before 'int'
    9 | int main()
      | ^~~
Language: C

#include <stdio.h>

struct Math{
    int m;
    int f;
    int r;
};

int main()
{
    struct Math a[65535];
    int i,t,sum;
    
    for(i=0;;i++){
        scanf("%d %d %d",a[i].m,a[i].f,a[i].r);
        if(a[i].m==0&&a[i].f==a0&&[i].r==0){
            t=i;
            break;
        }
    }

    for(i=0;i<t;i++){
        sum=a[i].m+a[i].f;
        if(a[i].m==-1||a[i].f==-1||sum<30){
            printf("F\n");
        }else if(sum>=80){
            printf("A\n");
        }else if(sum>=65&&sum<80){
            printf("B\n");
        }else if(sum>=50&&sum<65){
            printf("C\n");
        }else if(sum>=30&&sum<50){
            if(a[i].r>=50){
                printf("C\n");
            }else{
                printf("D\n");
            }
        }
    }
    return 0;
}

        
    

Compiler output:
main.c: In function 'main':
main.c:16:31: error: 'a0' undeclared (first use in this function); did you mean 'a'?
   16 |         if(a[i].m==0&&a[i].f==a0&&[i].r==0){
      |                               ^~
      |                               a
main.c:16:31: note: each undeclared identifier is reported only once for each function it appears in
main.c:16:35: error: expected expression before '[' token
   16 |         if(a[i].m==0&&a[i].f==a0&&[i].r==0){
      |                                   ^
Language: C

#include <stdio.h>

int main(void)
{

	int m,f,r;
	char rank;
	

	while (1){

		scanf("%d %d %d",&m,&f,&r);

		if(m==-1 && f==-1 && r==-1) break;

		else if(m+f<30)	{
			rank='F';
		}
		else if(m==-1 || f==-1)	{
			rank='F';
		}A
		
		else if(m+f>=80)	{
			rank='A';
		}
		else if(65<=m+f && m+f<80)	{
			rank='B';
		}
		else if(50<=m+f && m+f<65)	{
			rank='C';
		}
		else if(30<=m+f && m+f<50)	{
			if(r>=50)		{
				rank='C';
			}
			else	{
				rank='D';
			}
		}
		
		printf("%c\n",rank);
		
	}

	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:21:18: error: 'A' undeclared (first use in this function)
   21 |                 }A
      |                  ^
main.c:21:18: note: each undeclared identifier is reported only once for each function it appears in
main.c:21:19: error: expected ';' before 'else'
   21 |                 }A
      |                   ^
      |                   ;
   22 | 
   23 |                 else if(m+f>=80)        {
      |                 ~~~~
Language: C

#include<stdio.h>
int main(void){
    int m,f,r,p;
    char g;
    scanf("%d%d%d",&m,&f,&r);
    while(m!=-1 || f!=-1 || r!=-1){
        p=m+f;
        if(m==-1 || f==-1 || p<30 )){
            printf("F\n;");
        }else if(p>=80){
            printf("A\n;");
        }else if(p<80 && p>=65){
            printf("B\n;");
        }else if((p<65 && p>=50) || (p<50 && p>=30 && r>=50)){
            printf("C\n;");
        }else if(p<50 && p>=30 && r<50){
            printf("D\n;");
        }
        scanf("%d%d%d",&m,&f,&r);
    }
    return 0;
}

Compiler output:
main.c: In function 'main':
main.c:8:36: error: expected statement before ')' token
    8 |         if(m==-1 || f==-1 || p<30 )){
      |                                    ^
main.c:10:10: error: 'else' without a previous 'if'
   10 |         }else if(p>=80){
      |          ^~~~
Language: C

#include<stdio.h>
 
int main(void)
{
int m, f, r, p;
 
while(1){
sscanf("%d %d %d", &m, &f, &r);
if(m<0&&f<0&&r<0){ break; } 
p=m+f;
else if(m<0||f<0||p<30){ printf("F\n");}
else if(p<50){  
 if(r>=50){ printf("C\n");}
 else{ printf("D\n"); } 
}
else if(p<65){ printf("C\n"); }
else if(p<80){ printf("B\n"); }
else{ printf("A\n"); }
}
 
return 0;
}

Compiler output:
main.c: In function 'main':
main.c:8:20: error: passing argument 2 of 'sscanf' from incompatible pointer type [-Wincompatible-pointer-types]
    8 | sscanf("%d %d %d", &m, &f, &r);
      |                    ^~
      |                    |
      |                    int *
In file included from main.c:1:
/usr/include/stdio.h:431:43: note: expected 'const char *' but argument is of type 'int *'
  431 |                    const char *__restrict __format, ...) __THROW;
      |                    ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
main.c:11:1: error: 'else' without a previous 'if'
   11 | else if(m<0||f<0||p<30){ printf("F\n");}
      | ^~~~
Language: C

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

Compiler output:
main.c: In function 'main':
main.c:8:20: error: passing argument 2 of 'sscanf' from incompatible pointer type [-Wincompatible-pointer-types]
    8 | sscanf("%d %d %d", &m, &f, &r);
      |                    ^~
      |                    |
      |                    int *
In file included from main.c:1:
/usr/include/stdio.h:431:43: note: expected 'const char *' but argument is of type 'int *'
  431 |                    const char *__restrict __format, ...) __THROW;
      |                    ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
main.c:19:1: error: expected declaration or statement at end of input
   19 | }
      | ^
Language: C

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

Compiler output:
main.c: In function 'main':
main.c:19:1: error: expected declaration or statement at end of input
   19 | }
      | ^
Language: C

#include<stdio.h>

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

Compiler output:
main.c: In function 'main':
main.c:28:9: error: expected statement before ']' token
   28 |         ]
      |         ^
main.c:30:1: error: expected declaration or statement at end of input
   30 | }
      | ^
Language: C

#include<stdio.h>

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

Compiler output:
main.c: In function 'main':
main.c:24:5: error: expected declaration or statement at end of input
   24 |     return 0;
      |     ^~~~~~
Language: C

#include <stdio.h>

int main(){
   int m,f,r;
   do{
      scamf(" %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){
         printf("D\n");
      }else{
         printf("F\n");
      }

   }while(m!=-1 && f!=-1 && r!=-1);
   return 0;
}

Compiler output:
main.c: In function 'main':
main.c:6:7: error: implicit declaration of function 'scamf'; did you mean 'scanf'? [-Wimplicit-function-declaration]
    6 |       scamf(" %d %d %d", &m, &f, &r);
      |       ^~~~~
      |       scanf
Language: C

// aoj1.cpp : メイン プロジェクト ファイルです。

#include "stdafx.h"
#include<stdio.h>
#include<string>

using namespace System;

int main(array<System::String ^> ^args){
	int m,f,r;


	while( scanf("%d %d %d", &m, &f, &r) ){
		if( (m==-1)&&(f==-1)&&(r==-1) ){
			break;
		}
		if( (m==-1)||(f==-1) ){
			printf("F\n");
		}

		if(m+f >= 80){
			printf("A\n");
		}
		if( (m+f >= 65)&&(m+f < 80) ){
			printf("B\n");
		}
		if( (m+f >= 50)&&(m+f < 65) ){
			printf("C\n");
		}
		if( (m+f >= 30)&&(m+f < 50) ){
			if(r >= 50){
				printf("C\n");
			}else{
				printf("D\n");
			}
		}
		if(m+f < 30){
			printf("F\n");
		}
	}

	return 0;
}

Compiler output:
main.c:3:10: fatal error: stdafx.h: No such file or directory
    3 | #include "stdafx.h"
      |          ^~~~~~~~~~
compilation terminated.
Language: C

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

using namespace System;

int main(array<System::String ^> ^args){
	int m,f,r;


	while( scanf("%d %d %d", &m, &f, &r) ){
		if( (m==-1)&&(f==-1)&&(r==-1) ){
			break;
		}
		if( (m==-1)||(f==-1) ){
			printf("F\n");
		}

		if(m+f >= 80){
			printf("A\n");
		}
		if( (m+f >= 65)&&(m+f < 80) ){
			printf("B\n");
		}
		if( (m+f >= 50)&&(m+f < 65) ){
			printf("C\n");
		}
		if( (m+f >= 30)&&(m+f < 50) ){
			if(r >= 50){
				printf("C\n");
			}else{
				printf("D\n");
			}
		}
		if(m+f < 30){
			printf("F\n");
		}
	}

	return 0;
}

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

include<stdio.h>

int main(){

  int goukei,t1,t2,t3;

  while (1) {
    scanf("%d %d %d",&t1,&t2,&t3);
    if (t1==-1&&t2==-1&&t3==-1) {
      break;
    }

    goukei=t1+t2;

    if (t1==-1 || t2==-1) {
      printf("F\n");
    }
    else if(goukei>=80){
      printf("A\n");
    }
    else if(goukei>=65 && goukei <80){
      printf("B\n");
    }
    else if ((goukei>=50 && goukei<65) && t3>=50) {
      printf("C\n");
    }
    else if ((goukei>=30 && goukei<50) && (t1!=-1 || t2!=-1)) {
      printf("D\n");
    }
    else {
      printf("F\n");
    }

  }
  return 0;
}

Compiler output:
main.c:1:8: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
    1 | include<stdio.h>
      |        ^
Language: C

include<stdio.h>

int main(){

  int goukei,t1,t2,t3;

  while (1) {
    scanf("%d %d %d",&t1,&t2,&t3);
    if (t1==-1 && t2==-1 && t3==-1) {
      break;
    }

    goukei=t1+t2;

    if (t1==-1 || t2==-1) {
      printf("F\n");
    }
    else if(goukei>=80){
      printf("A\n");
    }
    else if(goukei>=65 && goukei <80){
      printf("B\n");
    }
    else if (goukei>=50 && goukei<65) {
      printf("C\n");
    }
    else if ((t3>=50)&& (goukei>=30 && goukei<50)) {
      printf("C\n");
    }
    else if (goukei>=30 && goukei<50) {
      printf("D\n");
    }
    else {
      printf("F\n");
    }

  }
  return 0;
}

Compiler output:
main.c:1:8: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
    1 | include<stdio.h>
      |        ^
Language: C

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

Compiler output:
main.c:1:9: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<' token
    1 | include <stdio.h>
      |         ^
main.c:4:7: error: stray '#' in program
    4 |   whil#include <stdio.h>
      |       ^
Language: C

#include<stdio.h>
main(){
  int m,f,r;
  m,f<=50;
  r<=100;
  while(1){
    scanf("%d %d %d",&m,&f,&r);
    if(m == -1 && f == -1 && r == -1)break;
    if(m+f >= 80){
      printf("A\n");
    }
    if(80 > m+f && m+f>= 65){
      printf("B\n");
    }
    if(65 > m+f && m+f >= 50){
      printf("C\n");
    }
    if(50 > m+f && m+f >= 35){
      printf("D\n");
    }
    if(50 > m+f && m+f >= 35 && r >= 50){
      printf("C\n");
    }
    if(m+f < 30){
      printf("F\n");
    }
    if(m == -1 || f == -1);
  }
}
  return 0;
}
   

Compiler output:
main.c:2:1: error: return type defaults to 'int' [-Wimplicit-int]
    2 | main(){
      | ^~~~
main.c:30:3: error: expected identifier or '(' before 'return'
   30 |   return 0;
      |   ^~~~~~
main.c:31:1: error: expected identifier or '(' before '}' token
   31 | }
      | ^
Language: C

#include<stdio.h>
main(){
  int m,f,r;
  while(1){
    scanf("%d %d %d",&m,&f,&r);
    if(m==-1 && f==-1 && r==-1){
      break;
    }
    if(m==-1 && f==-1){
      printf("F\n");
    }
    else if(m+f>=80){
      printf("A\n");
    }
    else if(m+f>=65 && m+r<80){
      printf("B\n");
    }
    else if(m+r>=50 && m+r<65 || m+r>=30 && 

Compiler output:
main.c:2:1: error: return type defaults to 'int' [-Wimplicit-int]
    2 | main(){
      | ^~~~
main.c: In function 'main':
main.c:18:5: error: expected expression at end of input
   18 |     else if(m+r>=50 && m+r<65 || m+r>=30 &&
      |     ^~~~
main.c:18:5: error: expected declaration or statement at end of input
main.c:18:5: error: expected declaration or statement at end of input
Language: C++

include <stdio.h>

int main(void)
{
  int m;
  int f;
  int r;

  while(1){
    scanf("%d %d %d", &m, &f, &r);
    int s = m + f;

    if(m + f + r == -3){//この方が節約できる？                                  
      break;
    }
    else if(m == -1 || f == -1){
      printf("F\n");
    }
    else if(s > 80){
      printf("A\n");
    }
    else if(s >= 65 && s < 80){
      printf("B\n");
    }
    else if(s >= 50 && s < 65){
      printf("C\n");
    }
    else if(s >= 30 && s < 50 && r >= 50){
      printf("C\n");
    }
    else if(s >= 30 && s < 50 && r < 50){
      printf("D\n");
    }
  }
  return 0;
}

Compiler output:
a.cc:1:1: error: 'include' does not name a type
    1 | include <stdio.h>
      | ^~~~~~~
Language: C++

#include <stdio.h>

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

Compiler output:
a.cc: In function 'int main()':
a.cc:20:51: error: expected identifier before '(' token
   20 |         else if((30 <= m + f) && (m + f < 50)) && (r >= 50)) {
      |                                                   ^
a.cc:23:51: error: expected identifier before '(' token
   23 |         else if((30 <= m + f) && (m + f < 50)) && (r < 50)) {
      |                                                   ^
Language: C++

#include<stdio.h>

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

Compiler output:
a.cc: In function 'int main()':
a.cc:10:25: error: expected primary-expression before '>' token
   10 |         }else if(m + f => 80 ){
      |                         ^
a.cc:12:25: error: expected primary-expression before '>' token
   12 |         }else if(m + f => 65 ){
      |                         ^
a.cc:14:25: error: expected primary-expression before '>' token
   14 |         }else if(m + f => 80 ||r => 50 ){
      |                         ^
a.cc:14:35: error: expected primary-expression before '>' token
   14 |         }else if(m + f => 80 ||r => 50 ){
      |                                   ^
Language: C++

#include <iostream>
using namespace std;

int main(){
  int m,f,r;
  while(cin >> m >> f >> r,!(m==-1 && f==-1 && r==-1)){
	if( m==-1 && f==-1) cout << 'F' << endl;
	else if( m+f >= 80) cout << 'A' << endl;
	else if( 80 > m+f && m+f >= 65) cout << 'B' << endl;
	else if( 65 > m+f && m+f >= 50) cout << 'C' << endl;
	else if( 50 > n+f && m+f >= 30){
	  if( r >= 50) cout << 'C' << endl;
	  else cout << 'D' << endl;
	}
	else if( m+f <  30) cout << 'F' << endl;

  }
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:11:23: error: 'n' was not declared in this scope
   11 |         else if( 50 > n+f && m+f >= 30){
      |                       ^
Language: C++

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

int main()
{
int m,f,r;
cin>>m>>f>>r;
if(m==-1 && f==-1 && r==-1)return 9;
if(m==-1||f==-1)
{
	cout<<"F"<<endl;
return 0;
}
if(m+f>=80)
{
	cout<<"A"<<endl;
	return 1;
}
if(m+f>=65 && m+f<80)
{
	cout<<"B"<<endl;
	return 2;
}
if(m+f>=50 && m+f<65)
{
	cout<<"C"<<endl;
return 3;
}

if(m+f>=30 && m+f<50)
{
if(r>=50)
{
	cout<<"C"<<endl;
return 4;
}
else
{
cout<<"D"<<endl;
return 5;
}

}

Compiler output:
a.cc: In function 'int main()':
a.cc:46:2: error: expected '}' at end of input
   46 | }
      |  ^
a.cc:8:1: note: to match this '{'
    8 | {
      | ^
Language: C++


		if(m == -1 && f == -1 && r == -1)break;
		
		if(m == -1 || f == -1) s = 'F';
			if(m+f >= 80)s = 'A';
			else if(m+f >= 65)s = 'B';
			else if(m+f >= 50)s = 'C';
			else if(m+f >= 30){
				s = 'D';
				if(r >= 50) s = 'C';
			}
			else s = 'F';
		printf("%c\n", s);
	}
	return 0;
}

Compiler output:
a.cc:2:17: error: expected unqualified-id before 'if'
    2 |                 if(m == -1 && f == -1 && r == -1)break;
      |                 ^~
a.cc:4:17: error: expected unqualified-id before 'if'
    4 |                 if(m == -1 || f == -1) s = 'F';
      |                 ^~
a.cc:5:25: error: expected unqualified-id before 'if'
    5 |                         if(m+f >= 80)s = 'A';
      |                         ^~
a.cc:6:25: error: expected unqualified-id before 'else'
    6 |                         else if(m+f >= 65)s = 'B';
      |                         ^~~~
a.cc:7:25: error: expected unqualified-id before 'else'
    7 |                         else if(m+f >= 50)s = 'C';
      |                         ^~~~
a.cc:8:25: error: expected unqualified-id before 'else'
    8 |                         else if(m+f >= 30){
      |                         ^~~~
a.cc:12:25: error: expected unqualified-id before 'else'
   12 |                         else s = 'F';
      |                         ^~~~
a.cc:13:23: error: expected constructor, destructor, or type conversion before '(' token
   13 |                 printf("%c\n", s);
      |                       ^
a.cc:14:9: error: expected declaration before '}' token
   14 |         }
      |         ^
a.cc:15:9: error: expected unqualified-id before 'return'
   15 |         return 0;
      |         ^~~~~~
a.cc:16:1: error: expected declaration before '}' token
   16 | }
      | ^
Language: C++

#include<stdio.h>

int main(){

int x,y,z;
while(1){

scanf("%d %d %d",&x,&y,&z);
if()x==-1&&y==-1&&z==-1)break;

if(x==-1||y==-1)printf("F\n");
else if(x+y>=80)printf("A\n");
else if(x+y>=65)printf("B\n");
else if(x+y>=50)printf("C\n");
else if(x+y>=30&&z>=50)printf("C\n");
else if(x+y>=30&&z<50)printf("D\n");
else if(x+y<30)printf("A\n");
}
return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:4: error: expected primary-expression before ')' token
    9 | if()x==-1&&y==-1&&z==-1)break;
      |    ^
a.cc:9:24: error: expected ';' before ')' token
    9 | if()x==-1&&y==-1&&z==-1)break;
      |                        ^
      |                        ;
Language: C++

#include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<utility>
#include<vector>
#include<cmath>
#include<cstring>
#include<cstdio>
#include<time.h>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double EPS=1e-10;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
int main(){
	int a,b,c;
	while(cin>>a>>b>>c,a+b+c!=-3)~
		if(a<0||b<0)cout<<"F"<<endl;
		else if(a+b>=80)cout<<"A"<<endl;
		else if(a+b>=65)cout<<"B"<<endl;
		else if(a+b>=30){
			if(c>=50)cout<<"C"<<endl;
			else cout<<"D"<<endl;
		}
		else cout<<"F"<<endl;
	}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:25:17: error: expected primary-expression before 'if'
   25 |                 if(a<0||b<0)cout<<"F"<<endl;
      |                 ^~
a.cc:26:17: error: 'else' without a previous 'if'
   26 |                 else if(a+b>=80)cout<<"A"<<endl;
      |                 ^~~~
a.cc: At global scope:
a.cc:34:1: error: expected declaration before '}' token
   34 | }
      | ^
Language: C++

/*
 * if, while, for????????????????????????
 */

#include <stdio.h>

int main(void)
{
    int mid, fin, agn, sum;
back : 
    scanf("%d %d %d", &mid, &fin, &agn);
    sum = mid + fin;
    switch (sum + agn) {
    case -3 : return 0;
    }
    printf("%c\n", mid == -1 ? 'F' fin == -1 ? 'F' : sum >= 80 ? 'A' : sum >= 65 ? 'B' : sum >= 50 || agn >= 50 ? 'C' : sum >= 30 ? 'D' : 'F');
    goto back;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:35: error: expected ':' before 'fin'
   16 |     printf("%c\n", mid == -1 ? 'F' fin == -1 ? 'F' : sum >= 80 ? 'A' : sum >= 65 ? 'B' : sum >= 50 || agn >= 50 ? 'C' : sum >= 30 ? 'D' : 'F');
      |                                   ^~~~
      |                                   :
Language: C++

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

Compiler output:
a.cc: In function 'int main()':
a.cc:6:9: error: 'scanf' was not declared in this scope
    6 |         scanf("%d %d %d", &m, &f, &r);
      |         ^~~~~
a.cc:25:9: error: 'printf' was not declared in this scope
   25 |         printf("%c\n", c);
      |         ^~~~~~
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)
Language: C++

#include <stdio.h>
#include <stdbool.h>

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

Compiler output:
a.cc: In function 'int main()':
a.cc:32:2: error: expected '}' at end of input
   32 | }
      |  ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include (stdio.h)

int main(void)
{
	int m, f, r;
	while (1)
	{
		scanf("%d %d %d", &m, &f, &r);
		if (m == -1 &&  f == -1 && r == -1) break;
		if ((m + f) < 30 ||  m == -1 || f == -1)
		{
			printf("F\n");
		}
		else if ((m + f) <= 49 && r < 50)
		{
			printf("D\n");
		}
		else if ((m + f) <= 64)
		{
			printf("C\n");
		}
		else if ((m + f) <= 79)
		{
			printf("B\n");
		}
		else
		{
			printf("A\n");
		}
		
	

Compiler output:
a.cc:1:10: error: #include expects "FILENAME" or <FILENAME>
    1 | #include (stdio.h)
      |          ^
a.cc: In function 'int main()':
a.cc:8:17: error: 'scanf' was not declared in this scope
    8 |                 scanf("%d %d %d", &m, &f, &r);
      |                 ^~~~~
a.cc:12:25: 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 | #include (stdio.h)
a.cc:16:25: error: 'printf' was not declared in this scope
   16 |                         printf("D\n");
      |                         ^~~~~~
a.cc:16:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:25: error: 'printf' was not declared in this scope
   20 |                         printf("C\n");
      |                         ^~~~~~
a.cc:20:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:24:25: error: 'printf' was not declared in this scope
   24 |                         printf("B\n");
      |                         ^~~~~~
a.cc:24:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:28:25: error: 'printf' was not declared in this scope
   28 |                         printf("A\n");
      |                         ^~~~~~
a.cc:28:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:29:18: error: expected '}' at end of input
   29 |                 }
      |                  ^
a.cc:7:9: note: to match this '{'
    7 |         {
      |         ^
a.cc:29:18: error: expected '}' at end of input
   29 |                 }
      |                  ^
a.cc:4:1: note: to match this '{'
    4 | {
      | ^
Language: C++

#include (stdio.h)

int main(void)
{
	int m, f, r;
	while (1)
	{
		scanf("%d %d %d", &m, &f, &r);
		if (m == -1 &&  f == -1 && r == -1) break;
		if ((m + f) < 30 ||  m == -1 || f == -1)
		{
			printf("F\n");
		}
		else if ((m + f) <= 49 && r < 50)
		{
			printf("D\n");
		}
		else if ((m + f) <= 64)
		{
			printf("C\n");
		}
		else if ((m + f) <= 79)
		{
			printf("B\n");
		}
		else
		{
			printf("A\n");
		}
	}
	return 0;
}
		
	

Compiler output:
a.cc:1:10: error: #include expects "FILENAME" or <FILENAME>
    1 | #include (stdio.h)
      |          ^
a.cc: In function 'int main()':
a.cc:8:17: error: 'scanf' was not declared in this scope
    8 |                 scanf("%d %d %d", &m, &f, &r);
      |                 ^~~~~
a.cc:12:25: 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 | #include (stdio.h)
a.cc:16:25: error: 'printf' was not declared in this scope
   16 |                         printf("D\n");
      |                         ^~~~~~
a.cc:16:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:20:25: error: 'printf' was not declared in this scope
   20 |                         printf("C\n");
      |                         ^~~~~~
a.cc:20:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:24:25: error: 'printf' was not declared in this scope
   24 |                         printf("B\n");
      |                         ^~~~~~
a.cc:24:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
a.cc:28:25: error: 'printf' was not declared in this scope
   28 |                         printf("A\n");
      |                         ^~~~~~
a.cc:28:25: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
Language: C++

	
	while (1){
		scanf("%d %d %d", &m, &f, &r);
		
		goukei = m + f;
		
		if (goukei == -2 && r == -1){
			break;
		}
		
		else if (m == -1 || f == -1){
			printf("F\n");
		}
		
		else if (goukei >= 80){
			printf("A\n");
		}
		
		else if (goukei >= 65 && goukei < 80){
			printf("B\n");
		}
		
		else if (goukei >= 50 && goukei < 65){
			printf("C\n");
		}
		
		else if (goukei >= 30 && goukei < 50){
			if (r >= 50){
				printf("C\n");
			}
			else {
				printf("D\n");
			}
		}
		
		else {
			printf("F\n");
		}
	}
	
	return (0);
}

Compiler output:
a.cc:2:9: error: expected unqualified-id before 'while'
    2 |         while (1){
      |         ^~~~~
a.cc:41:9: error: expected unqualified-id before 'return'
   41 |         return (0);
      |         ^~~~~~
a.cc:42:1: error: expected declaration before '}' token
   42 | }
      | ^
Language: C++

#include <iostream>


int main()
{
	int m;
	int f;
	int r;

	while (true){
		std::cin >> m;
	    std::cin >> f;
	    std::cin >> r;
		if (m != -1 && f!= && && r!= -1 )(x == -1 || y == -1) {
					break;
		} else if (m=-1 || f == -1 ) {
			std::cout << "F" << std::endl;
	    } else if (x + y >= 80) {
		    std::cout << "A" << std::endl;
	    } else if (65 <= x + y < 80) {
		    std::cout << "B" << std::endl;
	    } else if (50 <= x + y < 65) {
		    std::cout << "C" << std::endl;
	    } else if (30 <= x + y < 50 && z >= 50) {
		    std::cout << "C" << std::endl;
	    } else if (30 <= x + y < 50 && z < 50) {
		    std::cout << "D" << std::endl;
	    } else {
		    std::cout << "F" << std::endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:39: error: expected identifier before '&&' token
   14 |                 if (m != -1 && f!= && && r!= -1 )(x == -1 || y == -1) {
      |                                       ^~
a.cc:14:51: error: 'x' was not declared in this scope
   14 |                 if (m != -1 && f!= && && r!= -1 )(x == -1 || y == -1) {
      |                                                   ^
a.cc:14:62: error: 'y' was not declared in this scope
   14 |                 if (m != -1 && f!= && && r!= -1 )(x == -1 || y == -1) {
      |                                                              ^
a.cc:18:24: error: 'x' was not declared in this scope
   18 |             } else if (x + y >= 80) {
      |                        ^
a.cc:18:28: error: 'y' was not declared in this scope
   18 |             } else if (x + y >= 80) {
      |                            ^
a.cc:24:44: error: 'z' was not declared in this scope
   24 |             } else if (30 <= x + y < 50 && z >= 50) {
      |                                            ^
a.cc:32:2: error: expected '}' at end of input
   32 | }
      |  ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include <iostream>


int main()
{
	int m;
	int f;
	int r;

	while (true) {
		std::cin >> m;
	    std::cin >> f;
	    std::cin >> r;
		if (m == -1 && f== && && r== -1 ) {
					break;
		} else if (m=-1 || f == -1 ) {
			std::cout << 'F' << std::endl;
	    } else if (m + f >= 80) {
		    std::cout << 'A' << std::endl;
	    } else if (65 <= m + f < 80) {
		    std::cout << 'B' << std::endl;
	    } else if (50 <= m + f < 65) {
		    std::cout << 'C' << std::endl;
	    } else if (30 <= m + f < 50 && z >= 50) {
		    std::cout << 'C' << std::endl;
	    } else if (30 <= m + f < 50 && z < 50) {
		    std::cout << 'D' << std::endl;
	    } else {
		    std::cout << 'F' << std::endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:39: error: expected identifier before '&&' token
   14 |                 if (m == -1 && f== && && r== -1 ) {
      |                                       ^~
a.cc:24:44: error: 'z' was not declared in this scope
   24 |             } else if (30 <= m + f < 50 && z >= 50) {
      |                                            ^
a.cc:32:2: error: expected '}' at end of input
   32 | }
      |  ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include <iostream>


int main()
{
	int m;
	int f;
	int r;

	while (true) {
		std::cin >> m;
	    std::cin >> f;
	    std::cin >> r;
		if (m == -1 && f== && && r== -1 ) {
			break;
		} else if (m=-1 || f == -1 ) {
			std::cout << 'F' << std::endl;
	    } else if (m + f >= 80) {
		    std::cout << 'A' << std::endl;
	    } else if (65 <= m + f  {
		    std::cout << 'B' << std::endl;
	    } else if (50 <= m + f ) {
		    std::cout << 'C' << std::endl;
	    } else if (30 <= m + f )
			if (r>=50) {
				std::cout << 'C' << std::endl;
	        } else (30 <= m + f < 50 && z < 50) {
		        std::cout << 'D' << std::endl;
	    } else {
			std::cout << 'F' << std::endl;
		}
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:39: error: expected identifier before '&&' token
   14 |                 if (m == -1 && f== && && r== -1 ) {
      |                                       ^~
a.cc:20:35: error: expected ')' before '{' token
   20 |             } else if (65 <= m + f  {
      |                       ~           ^ ~
      |                                   )
a.cc:32:9: error: expected primary-expression before '}' token
   32 |         }
      |         ^
Language: C++

#include <iostream>


int main()
{
	int m;
	int f;
	int r;

	while (true) {
		std::cin >> m;
	    std::cin >> f;
	    std::cin >> r;
		if (m == -1 && f== && && r== -1 ) {
			break;
		} else if (m=-1 || f == -1 ) {
			std::cout << 'F' << std::endl;
	    } else if (m + f >= 80) {
		    std::cout << 'A' << std::endl;
	    } else if (m + f >=65) {
		    std::cout << 'B' << std::endl;
	    } else if (50 <= m + f ) {
		    std::cout << 'C' << std::endl;
	    } else if (30 <= m + f )
			if (r>=50) {
				std::cout << 'C' << std::endl;
	        } else (30 <= m + f < 50 && z < 50) {
		        std::cout << 'D' << std::endl;
	    } else {
			std::cout << 'F' << std::endl;
		}
	}
	return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:14:39: error: expected identifier before '&&' token
   14 |                 if (m == -1 && f== && && r== -1 ) {
      |                                       ^~
a.cc:27:45: error: 'z' was not declared in this scope
   27 |                 } else (30 <= m + f < 50 && z < 50) {
      |                                             ^
Language: C++

#include <iostream>


int main()
{
	int m;
	int f;
	int r;

	while (true) {
		std::cin >> m;
	    std::cin >> f;
	    std::cin >> r;
		
		if (m == -1 && f== && && r== -1 ) {
			break;
		} else if (m=-1 || f == -1 ) {
			std::cout << 'F' << std::endl;
	    } else if (m + f >= 80) {
		    std::cout << 'A' << std::endl;
	    } else if (m + f >=65) {
		    std::cout << 'B' << std::endl;
	    } else if (50 <= m + f ) {
		    std::cout << 'C' << std::endl;
	    } else if (30 <= m + f )
			if (r>=50) {
				std::cout << 'C' << std::endl;
	        } else {
		        std::cout << 'D' << std::endl;
	    } else {
			std::cout << 'F' << std::endl;
		}
	}
	return 0;
} 

Compiler output:
a.cc: In function 'int main()':
a.cc:15:39: error: expected identifier before '&&' token
   15 |                 if (m == -1 && f== && && r== -1 ) {
      |                                       ^~
Language: C++

#include <iostream>
   
int main()
{
	int m;
	int f;
	int r;
 
    while(true){
		std::cin m;
		std::cin f;
		std::cin r;
 
        if (m == -1 && f == -1 && r == -1) {
            break;
        } else if (m == -1 || f == -1) {
            std::cout << 'F' << std::endl;
        } else if (m + f >= 80) {
            std::cout << 'A' << std::endl;
        } else if (m + f >= 65) {
            std::cout << 'B' << std::endl;
        } else if (m + f >= 50) {
            std::cout << 'C' << std::endl;
        } else if (m + f >= 30) {
            if (r >= 50) {
                std::cout << 'C' << std::endl;
            } else {
                std::cout << 'D' << std::endl;
            }
        } else {
            std::cout << 'F' << std::endl;
        }
    }
   
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:25: error: expected ';' before 'm'
   10 |                 std::cin m;
      |                         ^~
      |                         ;
a.cc:11:25: error: expected ';' before 'f'
   11 |                 std::cin f;
      |                         ^~
      |                         ;
a.cc:12:25: error: expected ';' before 'r'
   12 |                 std::cin r;
      |                         ^~
      |                         ;
Language: C++

#include<iostream>

int main()
{
    int m,f,r;
    while(1){
        std::cin>>m>>f>>r;
        if (m==-1&&f==-1&&r==-1){
            break;
        }
        else if(m==-1||f==-1){
            std::cout<<"F"<<std::endl;
        }else if(m+f>=80){
            std::cout<<"A"<<std::endl;
        }else if(m+f>=65&&m+f<80){
            std::cout<<"B"<<std::endl;
        }else if(m+f>=50&&m+f<65){
            std::cout<<"C"<<std::endl;
        }else if(m+f>=35&&m+f<50&&r>=50){
            std::cout<<"C"<<std::endl;
        }else if(m+f>=35&&m+f<50&&r<50){
            std::cout<<"D"<<std::endl;

Compiler output:
a.cc: In function 'int main()':
a.cc:22:39: error: expected '}' at end of input
   22 |             std::cout<<"D"<<std::endl;
      |                                       ^
a.cc:21:40: note: to match this '{'
   21 |         }else if(m+f>=35&&m+f<50&&r<50){
      |                                        ^
a.cc:22:39: error: expected '}' at end of input
   22 |             std::cout<<"D"<<std::endl;
      |                                       ^
a.cc:6:13: note: to match this '{'
    6 |     while(1){
      |             ^
a.cc:22:39: error: expected '}' at end of input
   22 |             std::cout<<"D"<<std::endl;
      |                                       ^
a.cc:4:1: note: to match this '{'
    4 | {
      | ^
Language: C++

#include<iostream>

int main()
{
    int m,f,r;
    while(1){
        std::cin>>m>>f>>r;
        if (m==-1&&f==-1&&r==-1){
            break;
        }
        if(m==-1||f==-1){
            std::cout<<"F"<<std::endl;
        }else if(m+f>=80){
            std::cout<<"A"<<std::endl;
        }else if(m+f>=65&&m+f<80){
            std::cout<<"B"<<std::endl;
        }else if(m+f>=50&&m+f<65){
            std::cout<<"C"<<std::endl;
        }else if(m+f>=35&&m+f<50&&r>=50){
            std::cout<<"C"<<std::endl;
        }else if(m+f>=35&&m+f<50&&r<50){
            std::cout<<"D"<<std::endl;
        }else{
            std::cout<<"F"<<std::endl;
        }
    }
    return 0;

Compiler output:
a.cc: In function 'int main()':
a.cc:27:14: error: expected '}' at end of input
   27 |     return 0;
      |              ^
a.cc:4:1: note: to match this '{'
    4 | {
      | ^