实验2

Task1.c

#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;
        printf("20228329%04d\n", number);
    }
    return 0;
}

 answer1:在1至501间随机生成一个数

answer2:随机抽取5个人的学号

Task2.c

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main()
{
    int n, i, m;
    srand(time(0));
    i = rand() % 29 + 1;
    printf("猜猜2022年11月哪一天会是你的lucky day\n");
    printf("开始喽，你有三次机会，猜吧（1~30):");
    scanf_s("%d", &n);
    for (m = 1; m <3; m++)
    {
        if (n > i)
        {
            printf("你猜的日期晚了，你的lucky day已经过啦\n");
            printf("再猜：");
            scanf_s("%d", &n);
        }
        else if (n < i)
        {
            printf("你猜的日期早了，你的lucky day还没到呢\n");
            printf("再猜：");
            scanf_s("%d", &n);
        }
        else
        {
            printf("哇，猜中了:-)");
            break;
        }
    }
    if (m == 3)
    {
        printf("次数用完啦，偷偷告诉你：11月，你的lucky day是%d", i);
    }
    return 0;
}

Task3. c

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char n;
    while(scanf_s("%c",&n)!=EOF)
    {
        switch (n) {
        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;
        }
        getchar();
    }
    return 0;

}

Task4.c

#include<stdio.h>
#include<math.h>
int main()
{
    int n, a, m,i;
    double  s = 0.0;
    while (scanf_s("%d%d", &n, &a) != EOF)
    {
        m = a;
        printf("n=%d,a=%d", n, a);
        for (i = 1; i <= n; i++)
        {
            s +=(double) i / m;
            m = m * 10 + a;
        }
        printf(" s=%lf\n", s);
        s = 0;
    }
    return 0;
}

Task5.c

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int main()
{
    int a, b, c;
    for (a = 1; a < 10; a++)
    {
        for (b = 1; b <= a; b++)
        {
            c = a * b;
            printf("%dx%d=%d\t", a, b, c);
        }
        printf("\n");
    }
    system("pause");
    return 0;

 

Task6.c

#include<stdio.h>
#include<math.h>

int main()
{
    int i, j, m, t, n;

    for (;;)
    {
        scanf_s("%d", &n);

        printf("\n");

        t = 1;

        for (j = 1; j <= n; --n)
        {
            for (m= 1; m < t; ++m)
            {
                printf("\t");
            }

            for (i = 1; i <= 2 * n - 1; ++i)
            {
                printf(" O \t");

            }

            printf("\n");

            for (m = 1; m < t; ++m)
            {
                printf("\t");
            }

            for (i = 1; i <= 2 * n - 1; ++i)
            {
                printf("<H>\t");

            }

            printf("\n");

            for (m = 1; m < t; ++m)
            {
                printf("\t");
            }

            for (i = 1; i <= 2 * n - 1; ++i)
            {
                printf("I I\t");

            }

            printf("\n");

            ++t;
        }
    }

    return 0;
}