/in/foo.c: In function 'validate':
/in/foo.c:14:8: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
        if(k=1)
        ^~
/in/foo.c: At top level:
/in/foo.c:25:7: warning: return type of 'main' is not 'int' [-Wmain]
  void main()
       ^~~~