编辑代码

# include<stdio.h>
# include<string.h>
int main()
{
	int arr[] = { 4,6,10,12,20,30,50,70,88,100 };
	int k = 58;
	int left = 0;
	int sz = sizeof(arr) / sizeof(arr[0]);
	int right = sz - 1;
	while (left <= right)
	{
		int mid = (left + right) / 2;
		if (arr[mid] > k){
			right = mid - 1;
		}
 
		else if (arr[mid] < k){
		    left = mid + 1;
		}
 
		else{
			printf("找到了：%d\n", mid);
			break;
		}
    }
 
		if (left > right)//情况四：找不到
		{
			printf("找不到了\n");
		}
	return 0;
}