#include<stdio.h>
int main()
{
	int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
	int k = 18;
	int sz = sizeof(arr) / sizeof(arr[0]);
	//总大小/第一个元素大小=数组元素个数
	int L = 0;
	int R = sz - 1;
	while (L<=R)
	{
		int mid = (L + R) / 2;
		if (arr[mid] < k)
		{
			L = mid + 1;
		}
		else if (arr[mid] > k)
		{
			R = mid - 1;
		}
		else
		{
			printf("找到了：%d\n", mid);
			break;
		}
	}
	if (L > R)
	{
		printf("找不到了\n");
	}
	return 0;
}