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) );

    for(i = 0; i < N; ++i){
        number = rand()%65 + 1;
        printf("20238331%04d\n",number);
    }
    system("pause");
    return 0;
}

Q1:随机生成1~65之间的数

Q2：随机生成5个学号

task2

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

int main()
{
    char col;

    while(scanf("%c",&col)!=EOF){
        switch(col)
        {
        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;
               
        }
        getchar();
    }
    system("pause");
    return 0;
}

task3

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

int main()
{
    int lucky_day;
    int guess;
    int cnt;

    srand( time(0) );
    lucky_day = rand()%31 +1;

    printf("猜猜2024年5月哪一天会是你的lucky_day\n");
    printf("开始喽，你有三次机会，猜吧（1~31）:");

    for(cnt = 0;cnt < 3; ++cnt){
        scanf("%d",&guess);

        if(guess == lucky_day){
            printf("哇，猜中了：-）\n");
            system("pause");
            return 0;
        }
        if(guess > lucky_day)
           {printf("你猜的日期晚了，你的lucky_day在前面哦\n");
            printf("再猜（1~31）：");}
        if(guess < lucky_day)
           {printf("你猜的日期早了，你的lucky_day还没到呢\n");
            printf("再猜（1~31）：");}
        
    }printf("次数用完啦。偷偷告诉你，5月你的lucky_day是");
        printf("%d",lucky_day);
        printf("号\n");
        

    system("pause");
    return 0;

}

task4

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

int main()
{
    int n,a;
    double s;
    int down;
    double i;
    
    
    while(scanf("%d%d",&n,&a)!= EOF){
    s = 0.0;
    printf("n = %d, a = %d",n,a);

    down = a;
    for(i = 1;i <= n;++i){
        s = s + 1.0*i/down;
        down = down +  pow(10,i) * a;

        }
        printf(",s = %lf\n",s);
    }
        
        system("pause");
        return 0;
}

task5

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

int main()
{
    int i,j;
    

    for(i = 1;i<10;++i){
        
        for(j = 1;j<i+1;++j){
            printf("%d×%d= %d  ",j,i,i*j);
        }
        printf("\n");
    }

    system("pause");  
    return 0;
}

task6

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

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

    for(i=0;i<n;++i){
        for (j=1;j<=i;++j)
            printf("\t");
        for(k=2*(n-i)-1;k>0;--k)
           printf("  O\t");
        printf("\n");
        for(j=1;j<=i;++j)
           printf("\t");
        for(k=2*(n-i)-1;k>0;--k)
           printf(" <H>\t");
        printf("\n");
        for(j=1;j<=i;++j)
           printf("\t");
        for(k=2*(n-i)-1;k>0;--k)
           printf(" I I\t");
        printf("\n");}
    
    system("pause");
    return 0;

}