实验二

#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);
    }
    system("pause");
    return 0;

}

#include<stdlib.h>
#include<time.h>
int main()
{
    printf("猜猜2022年11月哪一天会是你的lucky day");
    int a, n, num;
    srand(time(0));
    a = rand() % 30 + 1;
    printf("%d", a);
    for (n = 1; n <= 3; n++) {
        scanf_s("%d", &num);
        if (num > a) {
            printf("你猜的日期晚了，你的lucky day已经过了\n");
            printf("再猜（1-30）：");
        }
        if (num < a) {
            printf("你猜的日期早了，你的lucky day还没到\n");
            printf("再猜（1-30）：");
        }

        if (num == a) {
            printf("猜中了");
            break;
        }

    }
    return 0;

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char colour;
    while (scanf_s("%c", &colour) != EOF)
    {
        switch (colour)
        {
        case 'r':printf("stop!"); break;
        case 'g':printf("go go go"); break;
        case 'y':printf("wait a minute"); break;
        default:printf("something must be wrong...");
        }getchar();
    }
    return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int main()
{
    unsigned int a = 1, n = 1, b = 1;
    while (scanf("%u%u", &n, &a) != EOF)
    {
        double s = 0, i, j;
        for (i = 1, b = a; i <= n; i++)
        {
            j = i / b;
            s = s + j;
            b = b * 10 + a;
        }
        printf("n=%u,a=%u,s=%lf\n", n, a, s);
    }


    system("pause");
    return 0;
}

#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;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int i, j, x, n;
    printf("input n:");
    scanf_s("%d", &n);
    for (i = 1; i <= n; i++)
    {
        for (j = 0; j < i - 1; j++)
        {
            printf("\t");
        }
        for (x = 0; x < 2 * (n - i) + 1; x++)

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

        for (j = 0; j < i - 1; j++)
        {
            printf("\t");
        }
        for (x = 0; x < 2 * (n - i) + 1; x++)

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

        for (j = 0; j < i - 1; j++)
        {
            printf("\t");
        }
        for (x = 0; x < 2 * (n - i) + 1; x++)

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

    }
}