Java常见编程习题：用面向对象思想求矩形面积 用面向对象思想求两点间的距离 猜数字

Java常见编程习题

1.用面向对象思想求矩形面积2.用面向对象思想求两点间的距离3.猜数字4.定义一个交通工具类

有什么错误或者需要改进的地方请各位多多指教，感谢。

1.用面向对象思想求矩形面积

import java.util.Scanner;public class RecArea {public static void main(String[] args) {//用面向对象思想求矩形面积Rec rec=new Rec();//创建矩形对象Scanner sc=new Scanner(System.in);System.out.println("enter length");//输入长度double length=sc.nextDouble();System.out.println("enter width");//输入宽度double width=sc.nextDouble();//将输入的长宽传给矩形对象rec.setLength(length);rec.setWidth(width);//调用成员方法求面积double area=rec.area();//格式输出保留3位小数System.out.printf("area is %.3f",area);}}class Rec{private double length;//矩形长度private double width;//矩形宽度//定义长宽对应的get，set方法public double getLength() {return length;}public void setLength(double length) {this.length = length;}public double getWidth() {return width;}public void setWidth(double width) {this.width = width;}//定义求面积的方法public double area(){return this.length*this.width;}}

运行结果

enter length3.4enter width5.6area is 19.040

2.用面向对象思想求两点间的距离

import java.util.Scanner;public class DistanceDemo {public static void main(String[] args) {//用面向对象思想求两点间的距离Scanner sc=new Scanner(System.in);System.out.println("enter first x");//输入第一个点的横坐标double x1=sc.nextDouble();System.out.println("enter first y");//输入第一个点的纵坐标double y1=sc.nextDouble();System.out.println("enter second x");//输入第二个点的横坐标double x2=sc.nextDouble();System.out.println("enter second y");//输入第二个点的纵坐标double y2=sc.nextDouble();//创建两个点并把输入的横纵坐标传入Distance d1=new Distance(x1,y1);Distance d2=new Distance(x2,y2);//调用方法求两点的距离double distanceGap=calculate(d1,d2);//格式输出保留三位小数System.out.printf("two distance gap is %.3f",distanceGap);}//定义求两点间距离的方法public static double calculate(Distance dot1,Distance dot2){double gap1=Math.pow(dot1.getY()-dot2.getY(), 2);//计算（y2-y1）的平方double gap2=Math.pow(dot1.getX()-dot2.getX(), 2);//计算（x2-x1）的平方return Math.sqrt(gap1+gap2);//计算根号(gap1+gap2)并返回}}class Distance{private double x;//点的横坐标private double y;//点的纵坐标//无参构造public Distance(){}//带参构造public Distance(double x,double y){this.x=x;this.y=y;}//x，y对应的get，set方法public double getX() {return x;}public void setX(double x) {this.x = x;}public double getY() {return y;}public void setY(double y) {this.y = y;}}

运行结果

enter first x4.3enter first y5.7enter second x3.8enter second y7.6two distance gap is 1.965

3.猜数字

import java.util.Random;import java.util.Scanner;public class GuessNum {public static void main(String[] args) {//猜数字Guess g=new Guess();//创建猜数字对象Random r=new Random();g.setNum(r.nextInt(100)+1);//给对象成员变量赋一个1到100间的随机整数guess(g);//调用方法进行猜测}public static void guess(Guess g){while(true){Scanner sc=new Scanner(System.in);System.out.println("enter your guess number(1~100)");//输入你猜的数字int num=sc.nextInt();if(num>g.getNum()){System.out.println("your number is big");//你猜的大了}else if(num<g.getNum()){System.out.println("your number is small");//你猜的小了}else{System.out.println("your number is right");//你猜对了，猜对则跳出循环，结束游戏break;}}}}class Guess{private int num;//要猜的数//num的set，get方法public int getNum() {return num;}public void setNum(int num) {this.num = num;}}

运行结果

enter your guess number(1~100)50your number is bigenter your guess number(1~100)25your number is smallenter your guess number(1~100)35your number is smallenter your guess number(1~100)45your number is smallenter your guess number(1~100)47your number is smallenter your guess number(1~100)49your number is bigenter your guess number(1~100)48your number is right

4.定义一个交通工具类

import java.util.Scanner;public class VehicleDemo {public static void main(String[] args) {//定义一个交通工具类Vehicle ve=new Vehicle(30,400);//创建一个交通工具并初始化Scanner sc=new Scanner(System.in);while(true){System.out.println("1.move start");//开始移动System.out.println("2.move end");//停止移动System.out.println("3.set speed");//修改速度System.out.println("4.set size");//修改交通工具大小System.out.println("5.speed up");//加速System.out.println("6.speed down");//减速System.out.println("7.show vehicle");//显示交通工具信息System.out.println("0.exit system");//退出int use=sc.nextInt();//接收用户输入switch(use){case 1:ve.moveStart();break;case 2:ve.moveEnd();break;case 3:System.out.println("enter speed");double speed=sc.nextDouble();ve.setSpeed(speed);break;case 4:System.out.println("enter size");double size=sc.nextDouble();ve.setSize(size);break;case 5:ve.speedUp();break;case 6:ve.speedDown();break;case 7:ve.show();break;case 0:System.exit(0);default:System.out.println("wrong number");break;}}}}class Vehicle{private double speed;//速度private double size;//大小public Vehicle(){}//无参构造public Vehicle(double speed,double size){this.speed=speed;this.size=size;}//带参构造public void moveStart(){System.out.println("move start……");}//开始移动public void moveEnd(){System.out.println("move end……");}//结束移动public void setSpeed(double speed){this.speed=speed;System.out.println();}//修改速度public void speedUp(){System.out.println("speed up……");this.speed++;}//加速public void speedDown(){System.out.println("speed down……");this.speed--;}//减速public void setSize(double size){this.size=size;System.out.println();}//修改大小public void show(){System.out.printf("speed is %.2f,size is %.2f\n",this.speed,this.size);}//显示信息}

运行结果

1.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system7speed is 30.00,size is 400.001.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system1move start……1.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system3enter speed601.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system4enter size6001.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system5speed up……1.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system7speed is 61.00,size is 600.001.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system6speed down……1.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system7speed is 60.00,size is 600.001.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system2move end……1.move start2.move end3.set speed4.set size5.speed up6.speed down7.show vehicle0.exit system0

感谢看到最后~

Java常见编程习题：用面向对象思想求矩形面积 用面向对象思想求两点间的距离 猜数字 定义一个交通工具类。