1 bool Check(int p)
 2 {
 3     return p;
 4 }
 5 int Bt(int l,int r)
 6 {
 7     int ans=0,mid;
 8     while(l<=r)
 9     {
10         mid=(l+r)>>1,
11         Check(mid)?ans=mid,l=mid+1:r=mid-1;
12     }
13     return ans;
14 }

 1 double DLT=0.1;
 2 bool Check(double p)
 3 {
 4     return p;
 5  } 
 6 int Bt(double l,double r)
 7 {
 8     double ans=0,mid;
 9     while(r-l>=DLT)
10     {
11         mid=(r+l)/2.0;
12         Check(mid)?ans=mid,l=mid:l=mid;
13     }
14 }