实验二

task1

#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;
}

task2

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main(){
    int x,n,ans;
    srand(time(0));
    x=rand()%30+1;
    printf("猜猜2022年4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;n++){
       scanf_s("%d",&ans);
       if(ans==x){
       printf("哇，猜中了");
       break;}

       else if(ans<x){
           printf("你猜的日期早了，你的lucky day还没到呢。");
       }
           else if(ans>x){
               printf("你猜的日期晚了，你的lucky day已经过了。");
           }
        if(n<=2){
               printf("\n再猜（1~30）：");
           }
    }
    if(n==4){
        printf("\n次数已经用完了，偷偷告诉你你的lucky day是4月%d号",x);
    }

    return 0;
}

task3

#include <stdio.h>

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

task4

#include <stdio.h>
#include <math.h>
int main()
{
    int i, n, a;
    printf("n=?,a=?\n");
    while (scanf_s("%d%d", &n, &a) != EOF)
    {
        float d = 0.0, s = 0.0;
        for (i = 1; i <= n; i++)
        {
            d += a * pow(10, i - 1);
            s += i / d;
        }
        printf("n = %d, a = %d, s= %f\n", n, a, s);
        printf("n=?,a=?\n");
    }
    return 0;

}

task5

#include <stdio.h>

int main()
{
    int column, line;
    for (column = 1; column <= 9; column++)
    {
        for (line = 1; line <= column; line++)
        {
            printf("%dx%d=%2d ", line, column, line * column);
        }
        printf("\n");
    }
    return 0;
}

task6.1

#include <stdio.h>

int main()
{
    int j, i;
    printf("input n:");
    scanf_s("%d", &i);
    for (j = 1; j <= i; j++)
    {
        printf(" o \n");
        printf("<H>\n");
        printf("I I\n\n");
    }
    return 0;
}

task6.2

#include <stdio.h>

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

    for (j = 1; j <= i; j++)
    {
        printf(" o   ");

    }
    printf("\n");


    for (j = 1; j <= i; j++)
    {
        printf("<H>  ");

    }
    printf("\n");


    for (j = 1; j <= i; j++)
    {
        printf("I I  ");

    }
    printf("\n");

    return 0;
}

task6.3

#include<stdio.h>
int main()
{
    int N, m, n, a;
    printf("input n：");
    scanf_s("%d", &N);
    for (m = 1; m <= N; m++)

    {
        for (n = 0; n <= m; n++)
            printf("\t");

        for (a = 0; a < N * 2 + 1 - m * 2; a++)
            printf(" o \t");
        printf("\n");

        for (n = 0; n <= m; n++)
            printf("\t");

        for (a = 0; a < N * 2 + 1 - m * 2; a++)
            printf("<H>\t");
        printf("\n");

        for (n = 0; n <= m; n++)
            printf("\t");

        for (a = 0; a < N * 2 + 1 - m * 2; a++)
            printf("I I\t");
        printf("\n");

    }
    return 0;
}