Language: C

xn];
int main()
{
int len_a,len_b;
	gets(a);
	gets(b);
	len_a=strlen(a);		
	len_b=strlen(b);
	if(len_a>len_b)
		printf("GREATER\n");
	if(len_a<len_b)
		printf("LESS\n");
	if(len_a==len_b)
	{	if(strcmp(a,b)>0)
			printf("REATER\n");
		if(strcmp(a,b)<0)
			printf("LESS\n");
		if(strcmp(a,b)==0)
			printf("EQUAL\n");
	
	
	}
	
	
	
	return 0;
}

Compiler output:
main.c:1:3: error: expected '=', ',', ';', 'asm' or '__attribute__' before ']' token
    1 | xn];
      |   ^
main.c: In function 'main':
main.c:5:9: error: implicit declaration of function 'gets' [-Wimplicit-function-declaration]
    5 |         gets(a);
      |         ^~~~
main.c:5:14: error: 'a' undeclared (first use in this function)
    5 |         gets(a);
      |              ^
main.c:5:14: note: each undeclared identifier is reported only once for each function it appears in
main.c:6:14: error: 'b' undeclared (first use in this function)
    6 |         gets(b);
      |              ^
main.c:7:15: error: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
    7 |         len_a=strlen(a);
      |               ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'strlen'
  +++ |+#include <string.h>
    1 | xn];
main.c:7:15: warning: incompatible implicit declaration of built-in function 'strlen' [-Wbuiltin-declaration-mismatch]
    7 |         len_a=strlen(a);
      |               ^~~~~~
main.c:7:15: note: include '<string.h>' or provide a declaration of 'strlen'
main.c:10:17: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   10 |                 printf("GREATER\n");
      |                 ^~~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'printf'
  +++ |+#include <stdio.h>
    1 | xn];
main.c:10:17: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   10 |                 printf("GREATER\n");
      |                 ^~~~~~
main.c:10:17: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:12:17: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   12 |                 printf("LESS\n");
      |                 ^~~~~~
main.c:12:17: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:14:20: error: implicit declaration of function 'strcmp' [-Wimplicit-function-declaration]
   14 |         {       if(strcmp(a,b)>0)
      |                    ^~~~~~
main.c:14:20: note: include '<string.h>' or provide a declaration of 'strcmp'
main.c:15:25: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   15 |                         printf("REATER\n");
      |                         ^~~~~~
main.c:15:25: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:17:25: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   17 |                         printf("LESS\n");
      |                         ^~~~~~
main.c:17:25: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:19:25: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
   19 |                         printf("EQUAL\n");
      |                         ^~~~~~
main.c:19:25: note: include '<stdio.h>' or provide a declaration of 'printf'