foo.cc: In function 'int main()':
foo.cc:84:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   84 |  scanf("%s", str1);
      |  ~~~~~^~~~~~~~~~~~
foo.cc:86:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   86 |  scanf("%s", str2);
      |  ~~~~~^~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务