作业2

#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() % 500 + 1;//从1~501中随机产生1个数
        printf("20228329%04d\n", number);
    }
    return 0;
}

//程序作用：随机点5个学号在202283290001-202283290501的学生

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
    srand(time(0));
    int day, gue;
    day = rand() % 29 + 1;
    printf("猜猜2022年11月哪一天会是你的lucky day\n开始喽，你有三次机会，猜吧（1~30）：\n");
    for (int i = 0; i < 3; i++)
    {
        scanf_s("%d", &gue);
        if (gue == day)
        {
            printf("哇，猜中了\n");
            break;
        }
        else if (gue > day)
        {
            printf("你的日期晚了，你的lucky day 已经过了\n");
            continue;
        }
        else (gue < day);
        {
            printf("你的日期早了，你的lucky day 还没到呢\n");
            continue;
        }

    }
    if (gue != day)
    {
        printf("次数用完啦下，偷偷告诉你:11月你的licky day 是%d号", day);
    }

    return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char a;

    for (;;)
    {
        scanf_s("%c", &a);
        getchar();

        switch (a)
        {
        case 'r':
            printf("stop!\n");
            break;
        case 'y':
            printf("wait a minute\n");
            break;
        case 'g':
            printf("go go go\n");
            break;
        default:
            printf("something must be wrong...\n");
        }
    }
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char a;

    for (;;)
    {
        scanf_s("%c", &a);
        getchar();

        switch (a)
        {
        case 'r':
            printf("stop!\n");
            break;
        case 'y':
            printf("wait a minute\n");
            break;
        case 'g':
            printf("go go go\n");
            break;
        default:
            printf("something must be wrong...\n");
        }
    }
}

#include<stdio.h>
#include<math.h>
int main()
{
    for (;;)
    {
        double sum = 0.0;
        int a, n, t;


        scanf_s("%d%d", &n, &a);
        printf("n=%d  a=%d\t" ,n, a);
        t = a;
        for (int i = 1; i <= n; i++)
        {

            sum = sum + i * 1.0 / t;
            t = 10 * t + a;
        }
        printf("sum=%lf", sum);

    }
    return 0;

}

#include<stdio.h>
#include<math.h>
int main()
{
    for (;;)
    {
        double sum = 0.0;
        int a, n, t;


        scanf_s("%d%d", &n, &a);
        printf("n=%d  a=%d\t" ,n, a);
        t = a;
        for (int i = 1; i <= n; i++)
        {

            sum = sum + i * 1.0 / t;
            t = 10 * t + a;
        }
        printf("sum=%lf", sum);

    }
    return 0;

}

#include<stdio.h>
#include<math.h>
int main() {
    int i, j, ans;

    for (i = 1; i <= 9; i++) {
        for (j = 1; j <= i; j++) {
            ans = i * j;
            printf("%d*%d=%d  ", j, i, ans);
        }
        printf("\n");
    }
    return 0;
}

#include<stdio.h>
int main()
{
    int n = 0;

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

            printf("\t");
        }

        printf(" o ");
        for (int j = 0; j < (n - 1 - i) * 2; j++)
        {

            printf("\t");
            printf(" o ");
        }

        printf("\n");
        for (int j = 0; j < i; j++)
        {

            printf("\t");
        }

        printf("<H>");
        for (int j = 0; j < (n - 1 - i) * 2; j++)
        {

            printf("\t");
            printf("<H>");
        }

        printf("\n");
        for (int j = 0; j < i; j++)
        {

            printf("\t");
        }

        printf("I I");
        for (int j = 0; j < (n - 1 - i) * 2; j++)
        {

            printf("\t");
            printf("I I");
        }

        printf("\n");

    }
    return 0;
}