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;
}

生成一个0~100的随机数

控制生成的数为四位

生成一个随机的编码

 

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;
}

重置它的值，会和原来值相加

break会直接终止循环，continu会跳过本次继续

不用，因为上面有代码做出判断

 

task3

#include <stdio.h>

int main() {
    char a;
    a = getchar();
    getchar();
    while (a != EOF) {
        switch (a) {
        case 'y':
            printf("wait a minute\n");
            break;
        case 'g':
            printf("go go go\n");
            break;
        case 'r':
            printf("stop!\n");
            break;
        default:
            printf("something must be wrong...\n");
            break;
        }
        a = getchar();
        getchar();
    }
    return 0;
}

 

task4

 

#include <stdio.h>

int main() {
    double a;
    double max = 0.0, min = 20000, b = 0.0;
    printf("输入一天内的若干笔开销，输入-1时终止");
    scanf_s("%lf", &a);
    getchar();
    while (a != -1) {
        if (a > max)
            max = a;
        if (a < min)
            min = a;
        b += a;
        scanf_s("%lf", &a);
        getchar();
    }
    printf("今天消费总额：%.1f\n", b);
    printf("今日最高一笔消费：%.1f\n", max);
    printf("今日最低一笔消费：%.1f\n", min);

    return 0;
}

 

task5

int main() {
    int d, x = 0;
    srand(time(0));
    printf("猜猜四月你的幸运日是哪天\n");
    printf("你有三次机会，猜吧：");
    scanf_s("%d", &d);
    int n = rand() % 30 + 1;
    if (d == n) {
        printf("猜对了");
    }
    while (d!=n) {
        while (x<2) {
            if (d < n) {
                printf("猜早了,");
                printf("再猜");
                scanf_s("%d", &d);
            }
            if (d > n) {
                printf("猜晚了,");
                printf("再猜");
                scanf_s("%d", &d);
            }
            
            x++;
            if (d == n) {
                printf("猜对了");
                break;
            }
        }
        if (x == 2) {
            printf("告诉你吧，是%d", n);
            break;
        }

    }
    

    return 0;
}

 

task6

#include <stdio.h>

int main() {
    int i=1, n,m, x = 1, z = 1, c = 1;
    scanf_s("%d", &m);
    n = 2 * m;
    while (c < n) {
        while (x < c) {
            printf("      ");
            x++;
        }
        while (i < n) {
            printf(" 0 ");
            printf("   ");
            i++;
        }
        printf("\n");
        i = z;
        x = 1;
        while (x < c) {
            printf("      ");
            x++;
        }
        while (i < n) {
            printf("<H>");
            printf("   ");
            i++;
        }
        printf("\n");
        i = z;
        x = 1;
        while (x < c) {
            printf("      ");
            x++;
        }
        while (i < n) {
            printf("I I");
            printf("   ");
            i++;
        }
        printf("\n");
        z += 2;
        i = z;
        x = 1;
        c++;
    }
    
    return 0;
}