foo.cc: In function 'int main()':
foo.cc:65:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   65 |  freopen("walk.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
foo.cc:66:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   66 |  freopen("walk.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:84:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   84 |   scanf("%d%d%d%d", &x1, &y1, &x2, &y2);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Found 10 testcases.