/in/foo.cc: In function 'int main()':
/in/foo.cc:40:29: warning: narrowing conversion of 'y[i]' from 'long long int' to 'double' inside { } [-Wnarrowing]
    b[++cnt]=(bian){i,i-1,y[i]};
                          ~~~^
/in/foo.cc:47:38: warning: narrowing conversion of 'yy[i]' from 'long long int' to 'double' inside { } [-Wnarrowing]
    b[++cnt]=(bian){i+bas,i+bas-1,yy[i]};
                                  ~~~~^
/in/foo.cc:74:9: warning: variable 'm1' set but not used [-Wunused-but-set-variable]
  double m1,m2;
         ^~
/in/foo.cc:74:12: warning: variable 'm2' set but not used [-Wunused-but-set-variable]
  double m1,m2;
            ^~
/in/foo.cc:75:6: warning: unused variable 'to1' [-Wunused-variable]
  int to1,to2;
      ^~~
/in/foo.cc:75:10: warning: unused variable 'to2' [-Wunused-variable]
  int to1,to2;
          ^~~