二分法查找

#include<stdio.h>//二分查找binary search
int main()
{
    //定义数组
    int array[]={0,5,13,19,22,41,55,68,72,81,98};
    int targetNumber,isFound=0;    //要查找的数字，查找结果。
    int i,index;//存放找到的数字的下标
    int low,high,mid;    //标识搜索区间的3个指针
    int arrLength = sizeof(array)/sizeof(array[0]);   //获得数组长度
    printf("请输入在以下数组中要查找的数字：\n");
    for(i=0;i<arrLength;i++)
    {
        printf("%d ",array[i]);
    }
    scanf("%d",&targetNumber);
    low=0;
    high=arrLength-1;
    index=-1;
    while(low<=high)
    {
        mid=(high+low)/2;
        if(array[mid]==targetNumber)
        {
            isFound=1;index=mid+1;break;
        }
        else if(array[mid]<targetNumber)
        {
            low=mid+1;
        }
        else if(array[mid]>targetNumber)
        {
            high=mid-1;
        }
    }

    if(isFound==0)
           printf("没有找到数字%d。\n",targetNumber);
    else
           printf("找到了，%d是第%d个数字\n",targetNumber,index);
    return 0;
}