/in/foo.cc: In function 'int main()':
/in/foo.cc:5:18: warning: too many arguments for format [-Wformat-extra-args]
  scanf("%c",&a,&b);
                  ^
/in/foo.cc:6:25: warning: too many arguments for format [-Wformat-extra-args]
         scanf("%c",&a,&b);
                         ^