实验二

实验一

#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;
}

 

问题一：随机抽取5个学员编号

问题二：随机生成1~100的数并赋值给number

问题三：将number位数变为四位，不足四位在前面加0

问题四：使每次输出结果不同

实验二

#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;
}

问题一：之前的金额不会重置

问题二：跳过循环重新输入

实验三

#include <stdio.h>

int main() {
    char ch;
    while (scanf_s("%c", &ch) != EOF) {
        if (ch == '\n') continue;

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

实验四

#include <stdio.h>

int main() {
    double expense, total = 0.0;
    double max_exp = 0.0, min_exp = 20000.0; 
    int count = 0; 

    printf("输入今日开销，直到输入-1终止：\n");

    while (1) {
        scanf_s("%lf", &expense);

        if (expense == -1) {
            break;
        }

        if (expense <= 0 || expense > 20000) {
            printf("输入无效，请输入0到20000之间的金额（不包含0）\n");
            continue;
        }

        total += expense;
        count++;

        if (expense > max_exp) {
            max_exp = expense;
        }

        if (expense < min_exp) {
            min_exp = expense;
        }
    }

    if (count == 0) {
        printf("今日无有效消费记录\n");
    }
    else {
        printf("今日累计消费总额: %.1f\n", total);
        printf("今日最高一笔开销: %.1f\n", max_exp);
        printf("今日最低一笔开销: %.1f\n", min_exp);
    }

    return 0;
}

实验五

#include <stdio.h>

int main() {
    int a, b, c;
    int temp;

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

 

实验六

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

int main() {
    int target, guess;

    srand((unsigned int)time(NULL));

    target = rand() % 30 + 1;

    printf("猜猜2026年4月哪一天是你的lucky day\n");
    printf("开始喽，你有3次机会，请猜吧(1~30)：");

    for (int i = 0; i < 3; i++) {
        scanf_s("%d", &guess);

        if (guess == target) {
            printf("哇，猜中了:)\n");
            
            return 0;
        }
        else if (guess > target) {
           
            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");
        }

        if (i < 2) {
            printf("再猜(1~30)：");
        }
    }

    printf("很遗憾，机会用完了。你的lucky day是：%d月%d日\n", 4, target);

    return 0;
}