实验2

实验任务1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
#define N1 80
#define N2 35
int main() {
    int cnt;
    int random_major, random_no;
    
    srand(time(NULL)); // 以当前系统时间作为随机种子
    
    cnt = 0;
    while(cnt < N) {
        random_major = rand() % 2;
        
        if(random_major) {
            random_no = rand() % N1 + 1;
            printf("20256343%04d\n", random_no);
        }
        else {
            random_no = rand() % N2 + 1;
            printf("20256136%04d\n", random_no);
        }
        
        cnt++;
    }
    return 0;
}

问题1：根据时间随机生成一个数

问题2：随机抽取4个学号

实验任务2

#include <stdio.h>

int main() {
    int choice, quantity;
    float total_price = 0, amount_paid, change;
    
    while (1) {
        printf("\n自动饮料售卖机菜单:\n");
        printf("1. 可乐 - 3 元/瓶\n");
        printf("2. 雪碧 - 3 元/瓶\n");
        printf("3. 橙汁 - 5 元/瓶\n");
        printf("4. 矿泉水 - 2 元/瓶\n");
        printf("0. 退出购买流程\n");
        printf("请输入饮料编号: ");
        scanf("%d", &choice);
        
        if (choice == 0)
            break;
            
        if (choice < 1 || choice > 4) {
            printf("无效的饮料编号，请重新输入。\n");
            continue;
        ｝
        
        printf("请输入购买的数量: ");
        scanf("%d", &quantity);
        
        if (quantity < 0) {
            printf("购买数量不能为负数，请重新输入。\n");
            continue;
        }
        
        if(choice == 1 || choice == 2)
            total_price += 3 * quantity;
        else if(choice == 3)
            total_price += 5 * quantity;
        else
            total_price += 2 * quantity;
            
        printf("请投入金额: ");
        scanf("%f", &amount_paid);
        
        change = amount_paid - total_price;
        printf("本次购买总价: %.2f 元\n", total_price);
        printf("找零: %.2f 元\n", change);
        
        total_price = 0;
    ｝
    
    printf("感谢您的购买，欢迎下次光临！\n");
    return 0;
}

问题1：重置前一次买东西的价钱

问题2：执行完前段语句后重复当前循环

实验任务3

#include <stdio.h>

int main() {
char x;
    while(scanf("%c",&x)!=EOF)
    {

        if(x=='r')
        {
            printf("stop!\n");
        }
    
        else if(x=='g')
        {
            printf("go go go\n");
        }
    
        else if(x=='y')
        {
            printf("wait a minute\n");
        }
    
        else
        {
            printf("something must be wrong\n");
        }
        while(getchar()!='\n');
    
    }
return 0;
}

 

实验任务4

#include <stdio.h>

int main() {
double x,max=0,min=20000,t=0;
    while(1)
    {
        scanf("%lf",&x);
        if(x==-1)
            {break;}
            
        t=t+x;
        if(max<x)
        {
            max=x;
        }
        if(min>x)
           {
            min=x;
           }
    
    }
    
    printf("今日总消费:%.1f\n",t);
    printf("今日最高消费:%.1f\n",max);
    printf("今日最低消费:%.1f\n",min);
return 0;
}

 

实验任务5

#include <stdio.h>
#include <math.h>

int main() {
    int a, b, c;
    
    while (scanf("%d %d %d", &a, &b, &c) != EOF) {
        
        if (a + b <= c || a + c <= b || b + c <= a) {
            printf("不能构成三角形\n");
        } 
        
        else if (a == b && b == c) {
            printf("等边三角形\n");
        } 
        
        else if (a == b || a == c || b == c) {
            printf("等腰三角形\n");
        } 
        
        else if (a*a + b*b == c*c || a*a + c*c == b*b || b*b + c*c == a*a) {
            printf("直角三角形\n");
        } 
        
        else {
            printf("普通三角形\n");
        }
    }
    
    return 0;
}

 

 

实验任务6

 

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

int main()
{
    srand(time(NULL));
    int i = rand() % 30 + 1; 
    int day, count = 0;
    
    printf("猜猜2025年11月哪一天是你的lucky day\n");
    printf("开始搂，你有三次机会，猜吧!(1~30):");
    
    for(count = 0; count < 3; count++)
    {
        scanf("%d", &day);
        
        if(day == i) 
        {
            printf("wa,猜中了！\n");
            break;
        } else if(day < i) 
        {
            printf("你猜的日期早了，你的lucky day还没到呢\n");
        } else {
            printf("你猜的日期晚了，你的lucky day在前面哦\n");
        }
        
        if(count < 2)
        {
            printf("再猜(1~30):");
        }
    }
    
    if(count == 3 && day != i) 
    {
        printf("次数用光啦。偷偷告诉你，11月你的lucky day是%d号\n", i);
    }
    
    return 0;
}