实验二

task.2

#include <stdio.h>

int main()
{
    char n;
    while(scanf("%c", &n)!=EOF)
    {
        getchar();
        
        switch(n){
        case'r':printf("stop!\n");break;
        case'g':printf("go go go\n");break;
        case'y':printf("wait a minute\n");break;
        default:printf("something must be wrong\n");break;
        }
    }
    
    return 0;
}

task.3

include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
    int n, i, day, c;
    day = rand()%30 + 1;
    c = 0;
    printf("猜猜2023年11月那天是你的lucky day\n");
    printf("开始喽，你有三次机会，猜吧\n");
    for(i = 1; i <= 3; ++i)
    {
        scanf("%d", &n);
    if(n < day)    {
    printf("你猜的日期早了，你的lucky day还没到呢\n");
    c++;
       if(c<3)
    printf("再猜\n");}
    else if(n > day){printf("你的日期晚了，你的lucky day已经过期\n");
    c++;
        if(c<3)printf("再猜\n");}
    
    else{printf("哇，猜中了\n");}
      break;
    }
    
    return 0;
}

task.4

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

task.5

#include <stdio.h>
int main()
{
    int i, j;
    for(i = 1;i<=9;i++)
    {
         for(j = 1;j<=i;j++)
    {
    printf("%d*%d = %d",i, j, i*j);}
    if(i!=j)
    printf("\n");
    }

    return 0;
}

task.6

int main()
{
    int n, i, j, m;
    scanf("%d", &n);
    for(i=n;i>=1;i--){
        for(m=1;m<=(n-1);m++)
        {
            printf("      ");
        }
        for(j=1;j<=(2*i-1);j++)
        {
            printf(" O ");
            printf("   ");
            
        }
        printf("\n");
        for (m=1;m<=(n-1);m++)
        {
            printf("      ");
        }
        for(j=1;j<=(2*i-1);j++)
        {
            printf("<H>");
            printf("      ");
        }
        printf("\n");
        for(m=1;m<=(n-i);m++)
        {
            printf("     ");
        }
        for(j=1;j<=(2*i-1);j++)
        {
            printf("       ");
            printf("I I");
        }
        printf("\n");
        
    }
        
        return 0;
}