实验2

task1源代码

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

#define N 5

int main() {
    int number;
    int i;

    srand(time(0)); // 以当前系统时间作为随机种子
    for (i = 0; i < N; ++i) {
        number = rand() % 100 + 1;
        printf("20490042%04d\n", number);
    }

    return 0;
}

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问题1：随机生成专业学员编号

问题2：line13是将1-100随机数赋值给numble

问题3：在42后再留四位数空间且补位为0

问题4：使生成数随机，弃掉后多次运行生成结果相同

task2源代码

#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_s("%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_s("%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_s("%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;
}

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问题1：去掉后第二次运行会将第一次的总价加在一起导致错误

问题2：跳过本次循环的剩下的所有语句，直接进入下一次循环

task3源代码

#include<stdio.h>
int main()
{
    char symble;
    while (scanf_s("%c", &symble) != EOF) {
        if (symble == '\n') {
            continue;
        }
        switch (symble)
        {
        case'r':
            printf("stop\n");
            break;
        case'g':
            printf("go go go\n");
            break;
        case'y':
            printf("wait a minute\n");
            break;
        default:
            printf("something must be wrong\n");
            break;
        }
    }
    return 0;
}

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task4源代码

#include<stdio.h>
#include<math.h>
int main()
{
    double sum = 0.0, max = 0.0, min = 20000.0, n;
    printf("一天内的若干笔开销:\n");
    
    while (1) {
        scanf_s("%lf", &n);
        if (n == -1) {
            break;
        }
        if (n <= 0 || n >= 20000) {
            printf("输入无效，输入0<n<20000的数值\n");
            continue;
        }
        sum += n;
        if (n > max) {
            max = n;
        }
        if (n < min) {
            min = n;
        }
    }
    printf("最高一笔开销：%.1f\n",max);
    printf("最低一笔开销:%.1f\n",min);
    printf("一天总开销:%.1f\n",sum);
    return 0;
}

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task5源代码

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main() {
    int a, b, c;
    while (scanf_s("%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;
}

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task6源代码

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int  main() {
    int lucky_day;
    int chance=3;
    int a;
    srand((unsigned  int)time(0));
    lucky_day = rand() % 30 + 1;
    printf("猜猜2026年4月哪一天是你的lucky day\n");
    while (chance > 0) {
        if (chance == 3) {
            printf("开始喽，你有三次机会，猜吧（1-30）:");
        }
        else {
            printf("再猜（1 - 30）:");
        }
        scanf_s("%d", &a);
        chance--;
        if (a == lucky_day) {
            printf("哇，猜中了:)\n");
            break;
        }
        
        else if (a > lucky_day) {
            printf("你猜的日期晚了，你的lucky day在前面哦\n");
            
        }
        else {
            printf("你猜的日期早了，你的lucky day还没到呢\n");
        }
        }
        printf("次数用光了。4月你的lucky day是%d号\n,",lucky_day);
    
        

    return  0;
}

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