实验2

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

#define N 5 

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

     srand(time(0)); 

     for(i=0; i<N; ++i) 
     {
         grade = rand()%4 + 2018;
         number = rand()%999 + 1; 
         printf("%d8330%04d\n", grade, number); 
      }

      return 0;
 }

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

 int main()
 {
     int luckyday, date;
    int i, j, k=0;
    
     srand(time(0));
     
    luckyday=rand()%30+1;
    
    printf("猜猜2022年4月哪天会是你的 lucky day\n");
     printf("开始喽，你有三次机会，猜吧（1~30）:");
    
   
     for(i=0; i<3; i++)
     {
         scanf("%d",&date);
         if(date==luckyday)
         {printf("哇，你猜中了");
          break;
         }
         else if(date<luckyday)
              {
                printf("你猜的日期早了，你的 lucky day 还没到呢\n");
                             printf("再猜（1~30）：");
                             
            }
         else
             {
               printf("你猜的日期晚了，你的 lucky day 已经过了\n");
               printf("再猜（1~30):");
        }
         k++; 
     }    
     if(k==3)
    printf("\n你的次数用完了，偷偷告诉你：4月，你的 lucky day 是%d号",luckyday);
    
     return 0;
 }

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

#include <stdio.h>
#include<stdlib.h>
double sum(int n,int a);
int main()
{
    int a,n;
    while((scanf("%d %d",&n,&a))!=EOF)
    {
        printf("n=%d,a=%d,s=%lf\n",n,a,sum(n,a));
    }
    return 0;
    
}

double sum(int n,int a)
{
    int j,k=0;
    double s=0.0,i;
    for(i=1.0;i<=n;i++)
    {
        k=k*10+a;
        s=s+i/k;
    }
    return s;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int i, j, k;
    for(i=1; i<=9; i++)
    {
        for(j=1; j<=i; j++ )
        {
           k=j*i;
           printf("%dx%d = %2d  ",j, i, k);
        }
    printf("\n");
    }
    return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int n, i;
    printf("input n:");
    scanf("%d",&n);
    for(i=0; i<n; i++)
    {
        printf(" O \n");
        printf("<H>\n");
        printf("I I\n\n");
    }
    
    return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int n, i;
    printf("input n:");
    scanf("%d",&n);
    
    for(i=0; i<n; i++)
    {
        printf("  O  ");
    }
    printf("\n") ;
    
    for(i=0; i<n; i++)
    {
    printf(" <H> ");
    }
    printf("\n") ;
    
    for(i=0; i<n; i++)
    {    
        printf(" I I ");
    }
    
    return 0;
}

#include<stdio.h>

int main()
{
    int n,i,j,k,m;
    printf("input n:");
    scanf("%d",&n);

 for (i = n; i > 0; i--)
    {
        for (k = n; k > i; k--)
            printf("     ");
            
        for (j = 2 * i - 1; j > 0; j--)
            printf("  O  ");
        printf("\n");
        
        for (k = n; k > i; k--)
            printf("     ");
            
        for (j = 2 * i - 1; j > 0; j--)
            printf(" <H> ");
        printf("\n");
        
        for (k = n; k > i; k--)
            printf("     ");
            
        for (j = 2 * i - 1; j > 0; j--)
            printf(" I I ");
        printf("\n");
    }
        
    return 0;
    
    
}