Java入门——day48

1.三维坐标向量类

设计一个描述三维坐标的向量类vector3D，成员如下：

数据成员：

• 三个坐标x，y，z，float类型，私有访问属性

公有函数成员：

• 三个参数均有默认值的构造函数，默认值为0，0，0；

• 完成输入输出，输出格式为(x, y, z)；

• 完成加法+、减法-、数乘*运算；

在主函数中定义两个vector3D类对象v1，v2，均不带参数，之后输入数字1或2选择为v1输入赋值，还是为v1和v2输入赋值，对v1和v2进行加、减运算，对v1进行数乘运算，乘数由用户输入，最后输出三种运算结果。

import java.util.Scanner;
//三维向量坐标类
public class Vector3D {
    private float x;
    private float y;
    private float z;
    public Vector3D() {
        this.x=0;
        this.y=0;
        this.z=0;
    }
    public Vector3D(float x, float y, float z) {
        this.x = x;
        this.y = y;
        this.z = z;
    }
    public void input() {
        Scanner in=new Scanner(System.in);
        x=in.nextFloat();
        y=in.nextFloat();
        z=in.nextFloat();
    }
    public void display() {
        System.out.println("("+x+"，"+y+"，"+z+")");
    }
    //加法
    public Vector3D add(Vector3D v) {
        float a=x+v.x;
        float b=y+v.y;
        float c=z+v.z;
        Vector3D p=new Vector3D(a,b,c);
        return p;
    }
    //减法
    public Vector3D sub(Vector3D v) {
        float a=x-v.x;
        float b=y-v.y;
        float c=z-v.z;
        Vector3D p=new Vector3D(a,b,c);
        return p;
    }
    //数乘
    public Vector3D mul(float n) {
        float a=x*n;
        float b=y*n;
        float c=z*n;
        Vector3D p=new Vector3D(a,b,c);
        return p;
    }
    public static void main(String[] args) {
        int n;
        Vector3D v1=new Vector3D();
        Vector3D v2=new Vector3D();
        Scanner in=new Scanner(System.in);
        System.out.println("1.为三维向量v1赋值并进行数乘运算");
        System.out.println("2.为三维向量v1、v2赋值并进行加、减运算");
        System.out.print("请输入你要进行的操作编号：");
        n=in.nextInt();
        if(n==1) {
            float t;
            Vector3D v;
            System.out.print("请输入v1的三维坐标：");
            v1.input();
            System.out.print("请输入乘数：");
            t=in.nextFloat();
            v=v1.mul(t);
            System.out.print("数乘结果为：");
            v.display();
        }
        if(n==2) {
            System.out.print("请输入v1的三维坐标：");
            v1.input();
            System.out.print("请输入v2的三维坐标：");
            v2.input();
            System.out.print("相加结果为：");
            (v1.add(v2)).display();
            System.out.print("相减结果为：");
            (v1.sub(v2)).display();
        }
    }
}

 

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2.电子钟

设计一款电子钟类，用于显示时、分、秒

• 含有形参有默认值的默认构造函数；

• 前缀++ 和 后缀—用于调整时间，每次调整均对秒进行调整，若秒满60，则分加1，若分满60则时加1，时满24，则清零重新开始；

• 设置函数用于输入（设定）时间；

• 设置函数用于输出时间。

import java.util.Scanner;
//电子钟类
public class Time {
    private int hour;
    private int minute;
    private int second;
    public Time() {
        this.hour = 0;
        this.minute = 0;
        this.second = 0;
    }
    public Time(int hour, int minute, int second) {
        this.hour = hour;
        this.minute = minute;
        this.second = second;
    }
    // 正计时
    public void zheng() {
        ++second;
        if (second >= 60) {
            second = 0;
            ++minute;
            if (minute >= 60) {
                minute = 0;
                ++hour;
                hour %= 24;
            }
        }
    }
    // 倒计时
    public void dao() {
        second--;
        if (second < 0) {
            minute--;
            second = 59;
        }
        if (minute < 0) {
            minute = 59;
            hour--;
        }
        if (hour < 0) {
            hour = 23;
        }
    }
    // 输入电子钟
    public void input() {
        Scanner in = new Scanner(System.in);
        hour = in.nextInt();
        minute = in.nextInt();
        second = in.nextInt();
    }
    // 输出电子钟
    public void output() {
        System.out.println(hour + ":" + minute + ":" + second);
    }
    public boolean dengYu(Time t) {
        if (hour == t.hour && minute == t.minute && second == t.second) {
            return true;
        } else {
            return false;
        }
    }
    public static void main(String[] args) throws InterruptedException {
        int n;
        Scanner in = new Scanner(System.in);
        // 菜单打印
        System.out.println("功能选择：");
        System.out.println("*********");
        System.out.println("1.钟表");
        System.out.println("2.正计时");
        System.out.println("3.倒计时");
        System.out.println("*********");
        System.out.print("请输入你的选择：");
        n = in.nextInt();
        if (n == 1) {
            System.out.print("请先校准时间：");
            Time t = new Time();
            t.input();
            while (true) {
                t.output();
                t.zheng();
                Thread.sleep(2000);
            }
        }
        if (n == 2) {
            Time t = new Time();
            while (true) {
                t.output();
                t.zheng();
                Thread.sleep(2000);
            }
        }
        if (n == 3) {
            Time t1 = new Time();
            Time t2 = new Time();
            System.out.print("请输入时间：");
            t1.input();
            while (true) {
                t1.output();
                t1.dao();
                Thread.sleep(2000);
                if (t1.dengYu(t2)) {
                    break;
                }
            }
            System.out.println("STOP!");
        }
    }
}

                                           

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3.分数类

import java.util.Scanner;
//分数类
public class Fraction {
    private int x;
    private int y;
    public Fraction() {
    }
    public Fraction(int x, int y) {
        this.x = x;
        this.y = y;
    }
    // 分数的输入
    public void input() {
        Scanner in = new Scanner(System.in);
        x = in.nextInt();
        y = in.nextInt();
    }
    // 分数的输出
    public void output() {

        if (y < 0) {
            x = -x;
            y = -y;
        }
        System.out.println(x + "/" + y);
    }
    // 求分子、分母的最大公因数
    public static int max(int a, int b) {
        int c = 0;
        while (a % b != 0) {
            c = a % b;
            a = b;
            b = c;
        }
        return c;
    }
    // 化简分数
    public Fraction simp() {
        int p = max(x, y);
        x = x / p;
        y = y / p;
        Fraction f = new Fraction(x, y);
        return f;
    }
    // 分数的加法
    public Fraction add(Fraction f) {
        int p = max(x * f.y + y * f.x, y * f.y);
        if (y == f.y) {
            Fraction c = new Fraction(x + f.x, y);
            return c;
        } else {
            Fraction c = new Fraction((x * f.y + y * f.x) / p, (y * f.y) / p);
            return c;
        }
    }
    // 分数的减法
    public Fraction sub(Fraction f) {
        int p = max(x * f.y - y * f.x, y * f.y);
        if (y == f.y) {
            Fraction c = new Fraction(x - f.x, y);
            return c;
        } else {
            Fraction c = new Fraction((x * f.y - y * f.x) / p, (y * f.y) / p);
            return c;
        }
    }
    // 分数的数乘
    public Fraction mul(int n) {
        int p = max(x * n, y);
        Fraction c = new Fraction((x * n) / p, y / p);
        return c;
    }

    // 判断关系：分数1==分数2
    public boolean dengYu(Fraction c) {
        int p1 = max(x, y);
        int p2 = max(c.x, c.y);
        if (x / p1 == c.x / p2 && y / p1 == c.y / p2) {
            return true;
        } else {
            return false;
        }
    }
    // 判断关系：分数1!=分数2
    public boolean buDengYu(Fraction c) {
        int p1 = max(x, y);
        int p2 = max(c.x, c.y);
        if (x / p1 == c.x / p2 && y / p1 == c.y / p2) {
            return false;
        } else {
            return true;
        }
    }
    // 判断关系：分数1>=分数2
    public boolean daYu(Fraction c) {
        int n1 = x * c.y;
        int n2 = y * c.x;
        if (n1 >= n2) {
            return true;
        } else {
            return false;
        }
    }
    // 判断关系：分数1<=分数2
    public boolean xiaoYu(Fraction c) {
        int n1 = x * c.y;
        int n2 = y * c.x;
        if (n1 <= n2) {
            return true;
        } else {
            return false;
        }
    }
    public static void main(String[] args) {
        int t, n;
        Fraction f1 = new Fraction();
        Fraction f2 = new Fraction();
        // 菜单打印
        System.out.println("功能选择：");
        System.out.println("**************");
        System.out.println("1.分数加法");
        System.out.println("2.分数减法");
        System.out.println("3.分数数乘");
        System.out.println("4.分数关系比较");
        System.out.println("**************");
        System.out.print("请输入你的选择：");
        Scanner in = new Scanner(System.in);
        t = in.nextInt();
        if (t == 1) {
            System.out.print("请输入分数1：");
            f1.input();
            System.out.print("请输入分数2：");
            f2.input();
            System.out.print("相加结果：");
            (f1.add(f2)).output();
        }
        if (t == 2) {
            System.out.print("请输入分数1：");
            f1.input();
            System.out.print("请输入分数2：");
            f2.input();
            System.out.print("相减结果：");
            (f1.sub(f2)).output();
        }
        if (t == 3) {
            System.out.print("请输入分数：");
            f1.input();
            System.out.print("请输入乘数：");
            n = in.nextInt();
            System.out.print("数乘结果：");
            (f1.mul(n)).output();
        }
        if (t == 4) {
            System.out.print("请输入分数1：");
            f1.input();
            System.out.print("请输入分数2：");
            f2.input();
            if (f1.daYu(f2)) {
                System.out.print("分数1==分数2");
            }
            if (f1.buDengYu(f2)) {
                System.out.println("分数1!=分数2");
            }
            if (f1.daYu(f2)) {
                System.out.println("分数1>=分数2");
            }
            if (f1.xiaoYu(f2)) {
                System.out.println("分数1<=分数2");
            }
        }
    }
}