/in/foo.c: In function 'main':
/in/foo.c:14:13: warning: implicit declaration of function 'abs' [-Wimplicit-function-declaration]
   { sum=sum+abs(a[i]-a[j]);
             ^~~
/in/foo.c:20:2: warning: 'min' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printf("%d",min);
  ^~~~~~~~~~~~~~~~