/in/foo.c: In function 'my_delete':
/in/foo.c:7:10: warning: 'return' with a value, in function returning void
   return 0;
          ^
/in/foo.c:4:6: note: declared here
 void my_delete(char s[], int si, int len) {
      ^~~~~~~~~
/in/foo.c:11:6: error: expected expression before ')' token
   if()
      ^
/in/foo.c: In function 'main':
/in/foo.c:18:5: warning: 'gets' is deprecated [-Wdeprecated-declarations]
     gets(s);
     ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c:17:18: warning: unused variable 'i' [-Wunused-variable]
     int si, len, i;
                  ^