/in/foo.c:2:6: warning: return type of 'main' is not 'int' [-Wmain]
 void main()
      ^~~~
/in/foo.c: In function 'main':
/in/foo.c:5:11: warning: format '%ld' expects argument of type 'long int *', but argument 2 has type 'int *' [-Wformat=]
  scanf("%ld%ld",&a,&b);
           ^
/in/foo.c:5:14: warning: format '%ld' expects argument of type 'long int *', but argument 3 has type 'int *' [-Wformat=]
  scanf("%ld%ld",&a,&b);
              ^
/in/foo.c:6:12: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'int' [-Wformat=]
  printf("%ld\n",a+b);
            ^