实验二

task1

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

#define N 5
#define N1 374
#define N2 465

int main() 
{
    int number;
    int i;

    srand( time(0) );

    for (i = 0;i < N;++i) {
        number = rand() % (N2 - N1 + 1) + N1;
        printf("202383290376%04d\n", number);
    }
    
    return 0;
}

task2（有问题）

#include<stdio.h>

int main(void)
{
    char n;
    n = getchar();
    while (scanf("%c,&n") != EOF)
    {
        if (n == 'r')
        {
            printf("stop!\n");
        }
        else if (n == 'g')
        {
            printf("go go go\n");
        }
        else if (n == 'y')
        {
            printf("wait a minuate\n");
        }
        else
        {
            printf("something must be wrong\n");
        }
    }

        return 0;
}

task3

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

#define N 1
#define N1 1
#define N2 30

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

    srand(time(0));

    for (i = 0;i < N;++i) {
        number = rand() % (N2 - N1 + 1) + N1;


    }
    printf("先偷偷把答案告诉你：%d\n", number);
    printf("猜猜2023年11月那天会是你的lucky day\n");
    printf("那么现在开始喽，你有三次机会，猜吧：");
    for (t = 1;t <= 3;t++) {

        scanf("%d", &n);

        if (n < number) {
            printf("你猜的日期早啦，还没到呢\n");

        }
        else if (n > number) {
            printf("你猜的日期晚啦，已经过了\n");
        }
        else {
            printf("恭喜你猜对啦\n");break;
            return n;
        }
    }
     printf("次数用完辣，偷偷告诉你，你的lucky day是：%d",number);
    return 0;
}

task4

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

task5

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

task6