实验二

task -1

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 5
int main()
{
    int grade, number;
    int i;

    srand(time(0)); //设定随机种子数为1

    for (i = 0; i < N; ++i)
    {
        grade = rand() % 4 + 2018; //生成一个2018-2021之间的随机数
        number = rand() % 999 + 1; //生成一个1-999之间的随机数
        printf("%d8330%04d\n", grade, number);
    }
    return 0;
}//程序功能是生成2018-2021级学生的随机学号

task-2

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 3
int main()
{
    int i,m,number;
    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):\t");
    srand(time(0));
    number = rand() % 30+1;
    for (i = 0; i < N; ++i)
    {
        scanf("%d",&m);
        if (m > number)
        {
            printf("你猜的日期晚了，你的lucky day已经过啦\n");
            printf("再猜(1`30):");
        }
        else if (m < number)
        {
            printf("你猜的日期早了，你的lucky day还没到呢\n");
            printf("再猜(1`30):");
        }
        else
        {
            printf("哇，猜中了");
                break;
        }
    }
    if(i==3)
    printf("次数用完啦，偷偷告诉你：4月，你的lucky day是%d号\n",number);
    return 0;
    
}

 task-3

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
    char m;
    while (scanf("%c", &m) != EOF)
    {
        
        if (m == 'r')
            printf("stop!\n");
        else if (m == 'g')
            printf("go go go\n");
        else if (m == 'y')
            printf("wait a minute\n");
        else
            printf("something must be wrong\n");
        getchar();
    }

    return 0;
}

 task-4

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<math.h>
int main()
{
    int i,n,a;
    while (scanf("%d %d",&n,&a) != EOF)
    {
        double m = 0.0;
        double s = 0.0;
        for (i = 1; i <= n; ++i)
        {
            
            m+=a*pow(10,i-1);
            s += i / m;
        }
        printf("n=%d,a=%d,s=%lf", n, a, s);
    }
    return 0;
}

 

task-5

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

 task-6.1

#include<stdio.h>
int main()
{
    int i,n;
    printf("input n:");
    scanf_s("%d", &n);
    for (i = 1; i <= n; ++i)
    {
        printf(" O\n");
        printf("<H>\n");
        printf("I I\n\n");
    }
}

task-6.2

#include<stdio.h>
int main()
{
    int i,n;
    printf("input n:");
    scanf_s("%d", &n);
    for (i = 1; i <= n; ++i)
        printf(" O     ");
    printf("\n");
    for (i = 1; i <= n; ++i)
        printf("<H>    ");
    printf("\n");
    for (i = 1; i <= n; ++i)
        printf("I I    ");
}

task-6.3

#include<stdio.h>
int main()
{
    int i,n,m;
    printf("input n:");
    scanf_s("%d", &n);
    for (n; n >= 0; --n)
    {
        m = (6 - n) * 7+1;
        printf("%*s", m, " ");
        for (i = 1; i <= 2 * n - 1; ++i)
            printf(" O     ");
        printf("\n");
        m = (6 - n) * 7+1;
        printf("%*s", m, " ");
        for (i = 1; i <= 2 * n - 1; ++i)
            printf("<H>    ");
        printf("\n");
        m = (6 - n) * 7+1;
        printf("%*s", m, " ");
        for (i = 1; i <= 2 * n - 1; ++i)
            printf("I I    ");
        printf("\n\n");
    }
}

实验总结：

1.用scanf()输入函数是一定记得加地址符&

2.每一次的输出printf（）要写在循环里

3.rand只能生成一次随机数，srand可生成多次

4.输入字符时要加' ',getchar()可以吞掉空格字符