/in/foo.cc: In function 'int main()':
/in/foo.cc:76:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d%d\n", &r, &c);
                           ^
/in/foo.cc:83:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
      scanf("%c", &ch);
                      ^
/in/foo.cc:86:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("\n");
                ^