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%d04\n",number);
    }
    return 0;
} 

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 1
int main()
{
    int number,n,a;
    srand(time(0));
    number=rand()%30+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): ");
    for(n=1;n<=3;){
        scanf("%d",&a);
        if(a==number)
        {printf("哇，猜中了：~\n");break;
        }
        else if(a<number)
        {printf("你猜的日期早了，你的lucky day还没到呢\n");
        }
        else
        {printf("你猜的日期晚了，你的lucky day已经过啦\n");
        }
        n++;
        if(n>3)break;
        printf("再猜(1~30): ");
        }
        if(n>3)
        {printf("次数用完，偷偷告诉你:11月，你的lucky day是%d号\n",number);
        }
        return 0;
    
}

#include<stdio.h>
#include<stdlib.h>
int main()
{
    char light;
    while(scanf("%c",&light)!=EOF){

    switch(light)
    {
     case 'y':printf("wait a minute\n");getchar();break;
     case 'g':printf("go go go\n");getchar();break;
     case 'r':printf("stop\n");getchar();break;
     default:printf("something must be wrong\n");getchar();break; 
     }

}
     return 0;
}

#include <stdio.h>
#include<math.h>
int main()
{
    int n, a, i;
    double s;
    while (1) {
        scanf_s("%d%d", &n, &a);
        for (i = 1, s = 0; i <= n; ++i);
        {
            s +=1.0 * i / pow(a, i);
        }
        printf("n=%d,a=%d,s=%lf", n, a, s);
        printf("\n");
    }

    return 0;
}

#include<stdio.h>
int main()
{
    int i, j;
    for (i = 1; i < 10; i++) {

        for (j = 1; j <= i; j++) {

            printf("%d*%d=%-3d ", j, i, i * j);
        }
        printf("\n");
    }
    return 0;
}

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


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


            }
            else
                printf("I I\t");
        }

        printf("\n");
        printf("\n");
    }
    return 0;
}