• 递归实现

int View::binarySearchRecursively(int arr[] , int low , int high , int nKey)
{
    if(low <= high)
    {
        int mid = (low + high)/2;
        if(arr[mid] == nKey)
        {
            return mid;
        }else if(arr[mid] < nKey)
        {
            return binarySearchRecursively(arr,mid+1,high,nKey);
        }else if(arr[mid] > nKey)
        {
            return binarySearchRecursively(arr,low,mid-1,nKey);
        }
    }
}

• 循环实现

int View::binarySearch(int arr[], int low, int high, int nKey)
{
    /*临时标记值*/
    int mid = 0;

    while (low <= high) {
        mid = (low + high)/2;
        if(arr[mid] == nKey)
        {
            break;
        }else if(arr[mid] < nKey)
        {
            low = mid + 1;
        }else{
            high = mid - 1;
        }
    }

    return mid;
}