/in/foo.cc: In function 'int main()':
/in/foo.cc:13:8: warning: variable 'b' set but not used [-Wunused-but-set-variable]
  int a,b,c,ans=0;
        ^
/in/foo.cc:13:10: warning: variable 'c' set but not used [-Wunused-but-set-variable]
  int a,b,c,ans=0;
          ^