/in/foo.cc: In function 'int main()':
/in/foo.cc:31:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,k;
        ^
/in/foo.cc:31:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k;
          ^
/in/foo.cc:24:17: warning: 'mn' may be used uninitialized in this function [-Wmaybe-uninitialized]
    re=1;if(b-a>i-mn||(b-a==i-mn&&mn<a)) a=mn,b=i;
                ~^~~
/in/foo.cc:20:20: note: 'mn' was declared here
  double mi=1e9;int mn;bool re=0;
                    ^~
/in/foo.cc:39:29: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  }printf("%d %d %.4f",a,b,l);
                             ^
/in/foo.cc:39:29: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]