C语言通过二分查找实现猜数字游戏

#include <stdio.h>
int main()
{
    int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
    //  下标          0 1 2 3 4 5 6 7 8 9
    int k = 7;//k是要查找的数字
    int i = 0;
    int sz = sizeof(arr) / sizeof(arr[0]);
     //sz为数组元素个数
    int flag = 0;//
    for (i = 0; i < sz; i++)
    {
        if (k == arr[i])
        {
            flag = 1;
            printf("找到了，下标是:%d\n", i);
            break;
        }
    }
    if (flag == 0)
        printf("找不到\n");

​​​​​​​    return 0;
}

#include <stdio.h>
int main()
{
	int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
	// 下标       0 1 2 3 4 5 6 7 8 9
	int k = 7;//k是要查找的数字
	int i = 0;
	int sz = sizeof(arr) / sizeof(arr[0]);
	//折半查找（二分查找），前提是数组有序
	int left = 0;
	int right = sz - 1;

	int flag = 0;
	while (left<=right)
	{
		int mid = (left + right) / 2;
		if (arr[mid] < k)
		{
			left = mid + 1;
		}
		else if (arr[mid] > k)
		{
			right = mid - 1;
		}
		else
		{
			printf("找到了，下标是：%d\n", mid);
			flag = 1;
			break;
		}
	}
	if (flag == 0)
		printf("找不到\n");

	return 0;
}

#include <stdio.h>
int main()
{
	int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
	//            0 1 2 3 4 5 6 7 8 9
	int k = 7;//k是要查找的数字
	int i = 0;
	int sz = sizeof(arr) / sizeof(arr[0]);
	//折半查找（二分查找），前提是数组有序
	int left = 0;
	int right = sz - 1;

	int flag = 0;
	while (left<=right)
	{
		int mid = left + (right - left) / 2;

		if (arr[mid] < k)
		{
			left = mid + 1;
		}
		else if (arr[mid] > k)
		{
			right = mid - 1;
		}
		else
		{
			printf("找到了，下标是：%d\n", mid);
			flag = 1;
			break;
		}
	}
	if (flag == 0)
		printf("找不到\n");

	return 0;
}

void menu()
{
    printf("*****************************\n");
    printf("*********   1. play  ********\n");
    printf("*********   0. exit  ********\n");
    printf("*****************************\n");
}

int main()
{
    int input = 0;
    do
    {
        menu();
        printf("请选择:>");
        scanf("%d", &input);
        switch (input)
        {
        case 1:
            printf("猜数字\n");
            break;
        case 0:
            printf("退出游戏\n");
            break;
        default:
            printf("选择错误\n");
            break;
        }
    } while (input);
    return 0;
}

void game()
{
    //1. 生成随机数
    int ret = rand() % 100 + 1;//0~99+1-->1~100
    //2. 猜数字
    int guess = 0;
    while (1)
    {
        printf("请猜数字:>");
        scanf("%d", &guess);
        if (guess < ret)
        {
            printf("猜小了\n");
        }
        else if (guess > ret)
        {
            printf("猜大了\n");
        }
        else
        {
            printf("恭喜你，猜对了\n");
            break;
        }
    }
}

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

void menu()
{
	printf("*****************************\n");
	printf("*********   1. play  *******\n");
	printf("*********   0. exit  ********\n");
	printf("*****************************\n");
}
//
//rand函数会返回一个0~32767之间的随机数
//
//时间戳

void game()
{
	//1. 生成随机数
	int ret = rand() % 100 + 1;//0~99+1-->1~100
	//2. 猜数字
	int guess = 0;
	while (1)
	{
		printf("请猜数字:>");
		scanf("%d", &guess);
		if (guess < ret)
		{
			printf("猜小了\n");
		}
		else if (guess > ret)
		{
			printf("猜大了\n");
		}
		else
		{
			printf("恭喜你，猜对了\n");
			break;
		}
	}
}

int main()
{
	int input = 0;
	//设置了随机数的生成器
	srand((unsigned int)time(NULL));
    //给srand传一个时间戳，是生成的数字足够随机
	do
	{
		menu();
		printf("请选择:>");
		scanf("%d", &input);
		switch (input)
		{
		case 1:
			game();
			break;
		case 0:
			printf("退出游戏\n");
			break;
		default:
			printf("选择错误\n");
			break;
		}
	} while (input);
	return 0;
}