实验2

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++;
    }
    system("pause");
    return 0;
 }

 

1是随机数重新生成

2随机生成5个学号

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;
 }

1多次购买时总价和找零会错误

2执行if语句，继续循环

任务3

#include<stdio.h>

 int main() {
         char n;
            while (scanf("%c", &n) != EOF) {
            getchar();
        
             if (n == 'r')
                     printf("stop!\n");
             else if (n == 'y')
                     printf("wait a minute\n");
             else if (n == 'g')
                     printf("go go go\n");
             else
                     printf("something must be wrong...\n");
        
            
            
    }
    
    return 0;
    
}

 任务4

#include<stdio.h>

 int main() {
     double c,s=0,max=0,min=20000;
     printf("输入今日开销，直到输入-1终止：\n");
     while (1) {
         scanf("%lf", &c);
         if (c == -1)
             break;
         
         if (c <= 0 || c > 20000)
             continue;
         
         if (c > max)
             max = c;
         if (c < min)
             min = c;
         s += c;

     }
     printf("今日累计消费总额：%.1lf\n", c);
     
     printf("今日最高一笔开销：%.1lf\n", max);
     printf("今日最低一笔开销：%.1lf\n", min);

     
     
    
    return 0;
    
}

 任务5

#include<stdio.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("不能构成三角型\n");
    else
    if (a == b || b == c || a == c)

        printf("等腰三角形\n");
    else if (a == b && b == c)
        printf("等边三角形\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;
    
}

 

 任务6

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

int main() {

    int n, m, i = 0;
    srand(time(NULL));
    n = rand() % 30+1;
    printf("猜猜2025年11月哪一天是你的lucky day\n");
    printf("开始喽，你有三次机会，猜吧（1~30）：");

    while (i < 3) {
    scanf_s("%d",&m);
    if (m == n) {
        printf("哇，你猜中了！");
        break;
    }
    else if (m < n)
        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在前面呢\n");
    if(i<2)
    printf("再猜(1`30)：");
    else
        printf("次数用光啦。偷偷告诉你，11月你的lucky day是%d号\n",n);
    i++;
}


    
    return 0;
    
}