实验2

task1
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
int main()
{
int number;
int i;
srand( time(0) ); // 以当前系统时间作为随机种子
for(i = 0; i < N; ++i) {
number = rand()%500 + 1;
printf("20228329%04d\n", number);
}
return 0;
}

task2
#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int main()
{
    int num, a, i;
    printf("猜猜2022年11月那一天会是你的lucky day\n");
    printf("开始喽，你有三次机会，猜吧（1~30): ");

    srand(time(0));

    for (i = 1; i <= 3; i++)
    {
        scanf_s("%d", &num);
        a = rand() % 30 + 1;
        if (num == a)
        {
            printf("哇,猜对了\n");
            break;
        }
        else if (num < a)
        {
            printf("你猜的日期早了，你的lucky day 还没到呢\n");
            printf("再猜：");
        }
        else
        {
            printf("你猜的日期晚了，你的lucky day已经过啦\n");
            printf("再猜：");
        }
    }
    
        printf("次数用完了，偷偷告诉你：11月你的lucky day是%d号\n", a);

    return 0;


}

task3
#include<stdio.h>
#include<stdlib.h>
int main()
{
    char A;
    int i;

    while (scanf_s("%c", &A) != EOF)
    {
        //getchar();
        //scanf_s("%c", &A);
        getchar();
        if (A == 'r') {
            printf("stop!\n");
        }
        else if (A == 'g') {
            printf("go go go\n");
        }
        else if (A == 'y') {
            printf("wait a minute\n");
        }
        else {
            printf("something must be wrong...\n");
        }
    }
        //system("pause");
    return 0;
}

task4
#include<stdio.h>
#include<stdlib.h>
#include<math.h>

int main()
{
    int a,n,i;
    int j ;
    double s;
    while (scanf_s("%d %d", &n, &a) != EOF)
    {
        j = 0, s = 0;
        for (i = 1; i <= n; i++)
        {
            j = j * 10 + a;
            s += i*1.0 / j;
            
        }
        
        printf("n=%d,a=%d,s=%.6f\n", n, a, s);
    }



    return 0;
}

task5
#include<stdio.h>
int main()
{
    int i, j,n;
    int m ;
    for (i = 1; i <= 9; i++)
    {
        
        for (j = 1; j <= i; j++)
        {
            m = i;
            n = j * m;
            printf("%d*%d=%d\t",j,m,n);
            m=m+1;
    
        }
        printf("\n");
    }
    return 0;
}

task6
#include<stdio.h>
int main()
{
    int i,j,n,x;
    scanf_s("%d", &n);
    for (i = 1; i <= n; i++)
    {
        for (x = 0; x < i - 1; x++)
        {
            printf("\t");
        }
        for (j = 1; j <= 2 *( n-i) +1; j++)
        {
            printf(" o\t");
        }
        printf("\n");
        for (x = 0; x < i - 1; x++)
        {
            printf("\t");
        }
        for (j = 1; j <= 2 * (n-i) +1; j++)
        {
            printf("<H>\t");
        }
        printf("\n");
        for (x = 0; x <i - 1; x++)
        {
            printf("\t");
        }
        for (j = 1; j <= 2 * (n - i) + 1; j++)
        {
            printf("I I\t");
        }
        printf("\n");
    }
    return 0;
}