二分查找的递归和非递归

int binsearch(int arr[],int len,int value){
    //low和high指向当前查找区间的两端,value为查找的关键字
    int low=0;
    int high=len-1;
    int mid;//当前区间的中间
    while(low <= high){
        mid = low + (high-low)/2;
        //mid = (low+high)/2;这样的写法会有整型相加溢出的bug
        if(arr[mid] == value){
            return mid;//返回下标
        }
        if(value < arr[mid]){
            high = mid-1;
        }
        else{
            low = mid+1;
        }
    }
    return -1;//未查找到返回-1
}

int binsearch(int arr[],int left,int right,int value){
    //递归出口
    if(left > right){
        return -1;
    }
    mid = low + (high-low)/2;
    if(arr[mid] == value){
        return mid;
    }
    else if(arr[mid] > value){
        return binsearch(arr,left,mid-1,value);
    }
    else{
        return binsearch(arr,mid+1，right,value);
    }
}

int seqsearch(int arr[],int len,int value){
    for(int i=0;i < len;++i){
        if(arr[i] == value){
            return i;
        }
    }
    return -1;//未查找到返回-1
}