foo.cc: In function 'int main()':
foo.cc:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
foo.cc:37:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d%d",&x1[i],&ydown[i],&x2[i],&y2[i]);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d%d",&stx,&sty,&edx,&edy);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:44:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lf",&v);    
     ~~~~~^~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务