/in/foo.cc: In function 'int main()':
/in/foo.cc:9:3: error: 'c' was not declared in this scope
   c = (a+b)%MOD;
   ^
/in/foo.cc:9:8: error: 'a' was not declared in this scope
   c = (a+b)%MOD;
        ^
/in/foo.cc:9:10: error: 'b' was not declared in this scope
   c = (a+b)%MOD;
          ^
/in/foo.cc:9:13: error: 'MOD' was not declared in this scope
   c = (a+b)%MOD;
             ^~~
/in/foo.cc:13:16: error: 'c' was not declared in this scope
  printf("%d\n",c%MOD);
                ^
/in/foo.cc:13:18: error: 'MOD' was not declared in this scope
  printf("%d\n",c%MOD);
                  ^~~