foo.cc: In function 'int main()':
foo.cc:39:29: warning: narrowing conversion of 'y[i]' from 'int' to 'double' inside { } [-Wnarrowing]
    b[++cnt]=(bian){i,i-1,y[i]};
                          ~~~^
foo.cc:46:38: warning: narrowing conversion of 'yy[i]' from 'int' to 'double' inside { } [-Wnarrowing]
    b[++cnt]=(bian){i+bas,i+bas-1,yy[i]};
                                  ~~~~^
foo.cc:33:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d",&n,&m,&x,&xx);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:37:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&y[i]);
   ~~~~~^~~~~~~~~~~~
foo.cc:44:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&yy[i]);
   ~~~~~^~~~~~~~~~~~~
foo.cc:101:25: warning: 'to2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   b[++cnt]=(bian){l1,to2+bas,m2};
                      ~~~^~~~
foo.cc:100:25: warning: 'to1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   b[++cnt]=(bian){l1,to1+bas,m1};
                      ~~~^~~~

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