实验2

task1

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

#define N 5

int main() {
    int number;
    int i;

    srand(time(0)); 
    for(i = 0; i < N; ++i) {
        number = rand() % 100 + 1;
        printf("20490042%04d\n", number);
    }

    return 0;
}

 Q1：生成的数在1-100之间

Q2：随机生成四位数字，不够的用0来补齐

Q3：随机生成学员编号202400420001~202400420100内的五个数字

task2

#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;
        }

        switch (choice) {
            case 1:
            case 2:
                total_price += 3 * quantity;
                break;
            case 3:
                total_price += 5 * quantity;
                break;
            case 4:
                total_price += 2 * quantity;
                break;
        }

        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;
}

 

Q1：将0赋值给total_price,使下一次循环总价钱从0开始计算

Q2：break是立即终止当前循环，跳出循环体，continue是跳过当前循环体剩余的代码

Q3：有必要，因为在当前循环体系内，若输入的不为01234，那么程序会仍然进行下去

task3

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

 task4

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

int main(){
    double sum=0.0,money=0.0,min=20000,max=0.0;

    printf("请输入今日开销，知道输入-1的时候终止：\n");
    
    while(1){
        scanf("%lf",&money);
        if(money == -1) 
            break;
        sum+=money;
        if(max<money)
            max = money;
        if(min>money)
            min = money;
        
    }

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

    system("pause");

return 0;
}

 

task5

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

int main(){
    int i,n=3,ans;
    int lucky_day;
    srand(time(0));
    lucky_day=rand()%30+1;
    printf("猜猜2025年4月哪天是你的lucky day\n");
    printf("开始咯，你有三次机会，猜吧（1~30);");
    for(i=0;i<n;++i)
    {
        scanf("%d",&ans);
        if(ans<=lucky_day) 
        {
        if(ans==lucky_day)
        {
        printf("哇，猜中了\n");
            break;
        }
        else
        {
            printf("\n早了，你的lucky day还没到呢\n");
            printf("再猜一次（1~30）：");
        }
        
    }
        else
        {
    printf("\n你猜的日期晚了，你的lucky day在前面哦\n");
    printf("再猜（1~30）:");
        }
    }
    if(i==3&&ans!=lucky_day)
        printf("\n次数用完了。偷偷告诉你四月你的lucky day是%d号\n",lucky_day);

    system("pause");

return 0;
}

 task6

#include<stdio.h>
int main(){
    int n,i,j,k;
    printf("input n:");
    scanf("%d",&n);

    for(j=0;n>=1;--n)
    {
        for(k=j;k>0;--k)
            printf("\t");
        for(i=n*2-1;i!=0;--i)
            printf(" o\t");
        printf("\n");
        for(k=j;k>0;--k)
            printf("\t");
        for(i=n*2-1;i!=0;--i)
            printf("<H>\t");
        printf("\n");
        for(k=j;k>0;--k)
            printf("\t");
        for(i=n*2-1;i!=0;--i)
            printf("| |\t");
        printf("\n");
        ++j;
    }
    return 0;
}