二分搜索（折半查找） binarySearch

http://blog.minidx.com/2008/02/03/468.html

 

 

 

#include <stdio.h>
#include <stdlib.h>



int BinarySearch(int *a,int x,int n)
{
    int left=0;
    int right=n-1;
    while(left<=right)
    {
        int middle=(left+right)/2;
        printf("left=%d, right=%d\n",left,right);
        if (x==a[middle])
            return middle;
        if (x>a[middle])
            left=middle+1;
        else
            right=middle-1;
    }
    return -1;
}

    
    
int main(void)
{
    int a[6] = {11,22,333,444,555,666 };
    int ret = 0;
    
    int num =0;
    
    printf("input the integer:\n");
    scanf("%d",&num);
    ret = BinarySearch(a,num,6);
    printf("ret=%d\n",ret);
    
    return 0;

}