题目汇总二

Question One

面向对象基础，声明 Box 类并实现对应操作

public class Box{public int length;public int width;public int height;public void setBox(int length, int width, int height){this.length = length;this.width = width;this.height = height;}public int volume(){return length * width * height;}public static void main(String[] args) {Box b = new Box();b.setBox(10, 10, 10);System.out.println(b.volume());}
}

Question Two

定义一个银行帐户类BankAccount实现银行帐户的概念，在BankAccount类中定义两个变量：“帐号” (account_number) 和"存款余额" (leftmoney)，再定义四个方法：“存款” (savemoney)、“取款” (getmoney) 、 “查询余额” (getleftmoney)、构造方法(BankAccount)。

最后，在main()方法中创建一个BankAccount类的对象ba，假设ba的账号为:123456，初始的存款余额为500元。首先向该账户存入1000元，再取出2000元。

no code

Question Three

java 里面类似 toString() 的方法

public class Main {public static void main(String[] args) {System.out.println(String.valueOf(12));System.out.println(String.valueOf(13.1231321d));System.out.println(String.valueOf(123333333333333312L));}
}

return type : String
parameter : int or long or double
role : tarns num into string

Question Four

自定义抛出异常

class myCustomException extends Exception {public myCustomException(String message) {super(message);}
}public class Main{public static void sort(){}public static void main(String[] args) {int[] nums = new int[100];for(int i = 0; i < 100; i ++){nums[i] = (int)(10000 * Math.random());try{if(nums[i] >= 5000){System.out.print(nums[i] + " ");throw new myCustomException("greater than or equal to 5000");}}catch (myCustomException e){System.out.println(e.toString());}}}
}

Question Five

GUI 实现二分猜数字游戏

import javax.swing.*;public class Main{public static void main(String[] args) {JOptionPane.showMessageDialog(null, "Give you an integer between 1 and 100, try to guess it !");int targetNum = (int)(Math.random() * 100) + 1;int guessNum = 0;while(true) {guessNum = Integer.parseInt(JOptionPane.showInputDialog("please guess the number:"));if (guessNum == targetNum) {JOptionPane.showMessageDialog(null, "You guessed the right number " + guessNum + " !");break;}else if(guessNum < targetNum){JOptionPane.showMessageDialog(null, "You guessed the lesser number " + guessNum + " !");}else{JOptionPane.showMessageDialog(null, "You guessed the greater number " + guessNum + " !");}}}
}

Question Six

接口示例

 interface MyComputer{int compute(int n, int m);}class Add implements MyComputer{public int compute(int n, int m){return n + m;}
}class Sub implements MyComputer{ // 定义了一个类Sub，实现了MyComputer接口public int compute(int n, int m){ // 实现了MyComputer接口中的compute方法，用于进行减法计算return n - m; // 返回n和m的差}
}class Mul implements MyComputer{ // 定义了一个类Mul，实现了MyComputer接口public int compute(int n, int m){ // 实现了MyComputer接口中的compute方法，用于进行乘法计算return n * m; // 返回n和m的积}
}class Div implements MyComputer{ // 定义了一个类Div，实现了MyComputer接口public int compute(int n, int m){ // 实现了MyComputer接口中的compute方法，用于进行除法计算try{ // 尝试进行除法计算return n / m; // 返回n除以m的结果}catch (Exception e){ // 捕获除零异常System.out.println(e.getMessage()); // 输出异常信息return -1; // 返回-1表示出现异常}}
}class UseComputer{ // 定义了一个类UseComputerpublic static void useCom(MyComputer com, int num1, int num2){ // 定义了一个静态方法useCom，接受一个MyComputer类型的对象和两个整数作为参数int result = com.compute(num1, num2); // 调用传入的MyComputer对象的compute方法进行计算System.out.println(result); // 输出计算结果}
}public class Main{ // 定义了一个公共类KY7_1public static void main(String[] args){ // 定义了一个公共的静态方法main，程序的入口点UseComputer.useCom(new Add(), 12, 6); // 使用Add类进行加法计算UseComputer.useCom(new Sub(), 12, 6); // 使用Sub类进行减法计算UseComputer.useCom(new Mul(), 12, 6); // 使用Mul类进行乘法计算UseComputer.useCom(new Div(), 12, 6); // 使用Div类进行除法计算UseComputer.useCom(new Div(), 12, 0); // 使用Div类进行除法计算，除数为0}
}

Question Seven

类继承多接口

interface AddInterface {double add(double a, double b);
}interface SubInterface {double sub(double a, double b);    
}interface MulInterface{double mul(double a, double b);
}interface DivInterface{double div(double a, double b);
}class Calculator implements AddInterface, SubInterface, MulInterface, DivInterface{public double add(double a, double b) {return a + b;}public double sub(double a, double b) {return a - b;}public double mul(double a, double b) {return a * b;}public double div(double a, double b) {try {return a / b;}catch (Exception e) {System.out.println(e.getMessage());return -1;}}
}public class Main {public static void main(String[] args) {Calculator calculator = new Calculator();// 测试加法double sum = calculator.add(5.0, 3.0);System.out.println("加法结果: " + sum);// 测试减法double difference = calculator.sub(5.0, 0.0);System.out.println("减法结果: " + difference);double mul = calculator.mul(5.0, 3.0);System.out.println(mul);double div = calculator.div(5.0, 3.0);System.out.println(div);System.out.println(calculator.div(5.0, 0.0));System.out.println(-5/0.0);}
}

Question Eight

多个类实现一个接口

interface areaOrVolume {double size(); // 抽象方法，用于计算图形的面积或体积
}class Rectangle implements areaOrVolume {private double width;private double height;public Rectangle(double width, double height) {this.width = width;this.height = height;}public double size(){return width * height;}
}class Circle implements areaOrVolume {private double r; // 圆的半径public Circle(double r) {this.r = r;}public double size() {return Math.PI * r * r; // 计算圆的面积}
}class Cylinder implements areaOrVolume {private double radius; // 圆柱体的底面半径private double height; // 圆柱体的高度public Cylinder(double radius, double height) {this.radius = radius;this.height = height;}public double size() {return Math.PI * radius * radius * height; // 计算圆柱体的体积}
}public class Main {public static void main(String[] args) {// 创建Rectangle类的对象o1Rectangle o1 = new Rectangle(5, 3);// 创建Circle类的对象o2Circle o2 = new Circle(4);// 创建Cylinder类的对象o3Cylinder o3 = new Cylinder(3, 5);// 分别调用对象o1、o2和o3的size()方法，计算面积或体积System.out.println("矩形的面积: " + o1.size());System.out.println("圆的面积: " + o2.size());System.out.println("圆柱体的体积: " + o3.size());}
}