【考研】折半查找法

int Bsearch(int R[],int low,int high,int val)
{
    int mid;
    while(low<=high)
    {
        mid=(low+high)/2;  //取当前表的中间位置 
        if(R[mid]==val)
            return mid;
        else if(R[mid]>val)//说明要在R[low，…，mid-1]中寻找 
            high=mid-1;
        else low=mid+1;    //说明要在R[mid+1，…，high]中寻找 
    }
    return -1;
}