/in/foo.cc: In function 'int main()':
/in/foo.cc:7:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,a,b,sum=0;
        ^
/in/foo.cc:7:10: warning: unused variable 'a' [-Wunused-variable]
  int i,j,a,b,sum=0;
          ^
/in/foo.cc:8:7: warning: unused variable 'c' [-Wunused-variable]
  char c,f[12]={"0123456789X"};
       ^