/in/foo.cc:57:5: warning: second argument of 'int main(int, char*)' should be 'char **' [-Wmain]
 int main(int argc,char argv[]){
     ^~~~
/in/foo.cc: In function 'int sum(int, int, int)':
/in/foo.cc:56:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^