Language: C

#include <stdio.h>

struct eye{
	int Left,Right;
};

int main(){
	eye A,B,C,D;
	A.Left=B.Left=C.Left=D.Left=0;
	A.Right=B.Right=C.Right=D.Right=0;
	float L,R;
	while(scanf("%f%f",&L,&R)!=EOF){
		if(L>=1.1) A.Left++;
		else if(L>=0.6) B.Left++;
		else if(L>=0.2) C.Left++;
		else D.Left++;
		if(R>=1.1) A.Right++;
		else if(R>=0.6) B.Right++;
		else if(R>=0.2) C.Right++;
		else D.Right++;
	}
	printf("%d %d\n",A.Left,A.Right);
	printf("%d %d\n",B.Left,B.Right);
	printf("%d %d\n",C.Left,C.Right);
	printf("%d %d\n",D.Left,D.Right);
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:8:9: error: unknown type name 'eye'; use 'struct' keyword to refer to the type
    8 |         eye A,B,C,D;
      |         ^~~
      |         struct 
main.c:9:10: error: request for member 'Left' in something not a structure or union
    9 |         A.Left=B.Left=C.Left=D.Left=0;
      |          ^
main.c:9:17: error: request for member 'Left' in something not a structure or union
    9 |         A.Left=B.Left=C.Left=D.Left=0;
      |                 ^
main.c:9:24: error: request for member 'Left' in something not a structure or union
    9 |         A.Left=B.Left=C.Left=D.Left=0;
      |                        ^
main.c:9:31: error: request for member 'Left' in something not a structure or union
    9 |         A.Left=B.Left=C.Left=D.Left=0;
      |                               ^
main.c:10:10: error: request for member 'Right' in something not a structure or union
   10 |         A.Right=B.Right=C.Right=D.Right=0;
      |          ^
main.c:10:18: error: request for member 'Right' in something not a structure or union
   10 |         A.Right=B.Right=C.Right=D.Right=0;
      |                  ^
main.c:10:26: error: request for member 'Right' in something not a structure or union
   10 |         A.Right=B.Right=C.Right=D.Right=0;
      |                          ^
main.c:10:34: error: request for member 'Right' in something not a structure or union
   10 |         A.Right=B.Right=C.Right=D.Right=0;
      |                                  ^
main.c:13:29: error: request for member 'Left' in something not a structure or union
   13 |                 if(L>=1.1) A.Left++;
      |                             ^
main.c:14:34: error: request for member 'Left' in something not a structure or union
   14 |                 else if(L>=0.6) B.Left++;
      |                                  ^
main.c:15:34: error: request for member 'Left' in something not a structure or union
   15 |                 else if(L>=0.2) C.Left++;
      |                                  ^
main.c:16:23: error: request for member 'Left' in something not a structure or union
   16 |                 else D.Left++;
      |                       ^
main.c:17:29: error: request for member 'Right' in something not a structure or union
   17 |                 if(R>=1.1) A.Right++;
      |                             ^
main.c:18:34: error: request for member 'Right' in something not a structure or union
   18 |                 else if(R>=0.6) B.Right++;
      |                                  ^
main.c:19:34: error: request for member 'Right' in something not a structure or union
   19 |                 else if(R>=0.2) C.Right++;
      |                                  ^
main.c:20:23: error: request for member 'Right' in something not a structure or union
   20 |                 else D.Right++;
      |                       ^
main.c:22:27: error: request for member 'Left' in something not a structure or union
   22 |         printf("%d %d\n",A.Left,A.Right);
      |                           ^
main.c:22:34: error: request for member 'Right' in something not a structure or union
   22 |         printf("%d %d\n",A.Left,A.Right);
      |                                  ^
main.c:23:27: error: request for member 'Left' in something not a structure or union
   23 |         printf("%d %d\n",B.Left,B.Right);
      |                           ^
main.c:23:34: error: request for member 'Right' in something not a structure or union
   23 |         printf("%d %d\n",B.Left,B.Right);
      |                                  ^
main.c:24:27: error: request for member 'Left' in something not a structure or union
   24 |         printf("%d %d\n",C.Left,C.Right);
      |                           ^
main.c:24:34: error: request for member 'Right' in something not a structure or union
   24 |         printf("%d %d\n",C.Left,C.Right);
      |                                  ^
main.c:25:27: error: request for member 'Left' in something not a structure or union
   25 |         printf("%d %d\n",D.Left,D.Right);
      |                           ^
main.c:25:34: error: request for member 'Right' in something not a structure or union
   25 |         printf("%d %d\n",D.Left,D.Right);
      |                                  ^