/in/foo.cc: In function 'long long int gcd(int, int)':
/in/foo.cc:10:7: warning: variable 'c' set but not used [-Wunused-but-set-variable]
   int c=a;
       ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:21:17: warning: too many arguments for format [-Wformat-extra-args]
  printf("%d",a,b);
                 ^
/in/foo.cc: In function 'long long int gcd(int, int)':
/in/foo.cc:16:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^