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

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

int main()
{
    int number;
    int n, i;
   

    srand(time(0));
    number = rand() % 30 + 1;
    printf("猜猜那一天会是你的Lucky day\n");
    printf("开始喽，你有三次机会，猜吧（1~30）\n");
    for (i = 1; i <= 3; i++)
    {
        scanf("%d", &n);

        if (n == number)
        {
            printf("你猜中了");
            break;
        }
        if (n < number)
        {
            printf("你猜的日期早了，Lucky day还没到呢\n");
        }
        if (n > number)
        {
            printf("你猜的日期晚了，Lucky day已经过啦\n");
        }
        if (i == 3) {
            printf("次数用光啦,偷偷告诉你：11月，你的Lucky day是%3d号\n", number);
            break;
        }
        if (i <= 2) {
            printf("再猜:\n");
        }
    }


    return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
    char x;

    while (scanf(" %c", &x ) != EOF)
    {

    switch (x)
    {
    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...");

    }


    }

    return 0;
}

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

    }

    return 0;
}

#include<stdio.h>
int main()
{
    int x, y;
    for (x = 1; x <= 9; x++)
    {

        for (y = 1; y <= x; y++)
            printf("%dx%d=%2d", x, y, x * y);
        printf("\n");
    }


    return 0;

}

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
    int i, m, n;
    scanf("%d", &n);
    for (i = 1; i <= n; i++) {
        for (m = 1; m < i; m++) {
            printf(" \t");
        }
        for (m = 1; m <= 2 * (n - i) + 1; m++) {
            printf(" O \t");
        }
        printf("\n");
        for (m = 1; m < i; m++) {
            printf(" \t");
        }
        for (m = 1; m <= 2 * (n - i) + 1; m++) {
            printf("<H>\t");
        }
        printf("\n");
        for (m = 1; m < i; m++) {
            printf(" \t");
        }
        for (m = 1; m <= 2 * (n - i) + 1; m++) {
            printf("I I\t");
        }
        printf("\n");
        printf("\n");
    }
    return 0;
}