/in/foo.c: In function 'main':
/in/foo.c:4:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%ld",&n);
  ^~~~~
/in/foo.c:4:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:4:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:14:25: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
   for(j=0;j<n;j++) sum+=abs(s[i]-s[j]);
                         ^~~
/in/foo.c:17:4: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    printf("%ld",min);
    ^~~~~~
/in/foo.c:17:4: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:17:4: note: include '<stdio.h>' or provide a declaration of 'printf'