二分查找算法

c语言：

/*
二分法查找
*/

#define N 6
main()
{
    int a[N]={1,2,3,5,7,10};
    int searchNum=5;
    int index;

    index=search(a,searchNum);
    if(index!=-1)
        printf("a[%d]=%d",index,searchNum);
    else
        printf("not found!");

    getch();
}

int search(int a[],int num)
{
    int begin,middle,end;
    begin=0;
    end=N-1;
    middle=(begin+end)/2;

    while(a[middle]!=num && !(middle==begin&&middle==end))
    {
         if(a[middle]<num)
             begin=middle+1;
         else
             end=middle;
         middle=(begin+end)/2;
    }
    if(a[middle]==num)
        return middle;
    else
        return -1;
}

c#：

using System;

namespace suafa
{
    /**//// <summary>
    /// Class1 的摘要说明。
    /// </summary>
    class Class1
    {
        /**//// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            //
            // TODO: 在此处添加代码以启动应用程序
            //
            int[] a = new int[]{1,2,3,5,7,10};
            int searchNum = 100;
            int index = search(a, searchNum);
            if(index != -1)
            {
                Console.Write("a[" + index + "]=" + searchNum);    
            }
            else
            {
                Console.Write("找不到");
            }
            Console.ReadLine();
        }

        static private int search(int[] a, int num)
        {
            int length = a.Length-1;
            int begin, middle, end;
            begin = 0;
            end = length;
            middle= Convert.ToInt32((begin+end)/2);

            while(a[middle]!=num && !(middle==begin && middle==end))
            {
                if(a[middle] < num)
                {
                    begin = middle + 1;
                }
                else
                {
                    end = middle;
                }
                middle=Convert.ToInt32((begin+end)/2);
            }
            
            if(a[middle] == num)
            {
                return middle;
            }
            else
            {
                return -1;
            }
        }
    }
}

asp：

<!--二分查找法-->
<%
    
dim a
dim index
dim searchNum
a = array(1,2,3,5,7,10)
searchNum = 5

index = search(a,searchNum)
if index <> -1 then
    response.write "a(" & index & ")=" & searchNum 
else
    response.write "找不到"
end if

function search(a(), num)
    dim bound
    bound = ubound(a)
    dim begin, middle, ending
    begin = 0
    ending = bound
    middle = int((begin+ending)/2)
    
    do while a(middle)<>num and not(begin=middle and ending=middle)
        if a(middle) < num then
            begin = middle + 1
        else
            ending = middle
        end if
        middle = int((begin+ending)/2)
        
    loop
    if a(middle) = num then
        search = middle
    else
        search = -1
    end if
end function

    

%>