foo.cc: In function 'int main()':
foo.cc:67:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   67 |  freopen("walk.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:68:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   68 |  freopen("walk.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Found 10 testcases.