我的第35个代码

创建函数利用二分法

#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<math.h>
#include<string.h>

int judge(int arr[], int k,int length)
{
	int left = 1;
	int right = length;
	while (left<=right)
	{
		int mid = (right + left) / 2;
		if (arr[mid - 1] < k)
		{
			left = mid + 1;
		}
		else if (arr[mid - 1 > k])
		{
			right = mid - 1;
		}
		else if (arr[mid - 1] == k)
			return mid - 1;	
	}
	return -1;
}


int main()
{
	char arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
	int length = strlen(arr);
	int x = 0;
	printf("请输入1-10内您想查找的数字\n");
	scanf("%d", &x);
	int ret = judge(arr, x,length);
	if (ret == -1)
	{
		printf("找不到这个数字\n");
	}
	else
	{
		printf("找到了，下标是%d\n", x -1);
	}
	return 0;
}