20. 折半查找有序数组

//折半查找  前提有序数组
#include <stdio.h>
#define N 10
int main(void)
{
    int arr[N] = {1,2,3,4,5,6,7,8,9,10};//升序
    int findDate = 10;
    int idx = -1;
    int left = 0,right=N-1;
    int mid;

    while(left<=right)
    {
        mid = (left+right)/2;
        if(findDate == arr[mid])
        {
            idx = mid;
            break;
        }
        else if(findDate > arr[mid])
        {
            left = mid+1;
        }
        else
            right = mid-1;
    }
    if(idx == -1)
        printf("find none\n");
    else
        printf("findDate's idx == %d\n",idx);


    return 0;
}