編寫(xiě)一段代碼來(lái)計(jì)算正方形的面積和周長(zhǎng)？Java程序

import java.util.Scanner

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public class abc {

public static void main(String[] args){

Scanner input = new Scanner(System.in);

System.out.println("輸入邊長(zhǎng)：");

double a = input.nextDouble();

double area = a*a;

double length=4*a;

System.out.println(area);

System.out.println(length);

寫(xiě)一個(gè)java程序，使其畫(huà)一個(gè)正方形并改變它的顏色（每秒鐘改變一次）。求完整代碼謝謝

按照你的要求,編寫(xiě)的Java程序如下

import?java.awt.Color;

import?java.awt.Graphics;

import?javax.swing.JFrame;

public?class?F?extends?JFrame?implements?Runnable{

Color[]?colors?=?{Color.red,Color.orange,Color.yellow,Color.green,Color.cyan,Color.blue,Color.magenta,Color.black};??

int?i=0;

F(){

setTitle("變色正方形");

setSize(400,?400);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setLocationRelativeTo(null);

setVisible(true);

}

public?void?paint(Graphics?g){

g.setColor(colors[i]);

g.drawRect(100,100,200,200);

}

@Override

public?void?run()?{

while(true){

try?{

Thread.sleep(1000);

}?catch?(InterruptedException?e)?{

e.printStackTrace();

}

if(i7)

i++;

else

i=0;

repaint();

}

}

public?static?void?main(String[]?args)?{

F?f=new?F();

Thread?t=new?Thread(f);

t.start();

}

}

運(yùn)行結(jié)果

用java編寫(xiě)一個(gè)名為Square（正方形）的類(lèi)，并按要求完成如下封裝

隨便寫(xiě)寫(xiě)??? 未測(cè)試

package?com.leejiliang.HomeworkDemo2;

public?class?Test?{

public?static?void?main(String[]?args)?{

Square[]?squares?=?new?Square[10];

for?(int?i?=?0,?k?=?squares.length;?i??k;?i++)?{

squares[i]?=?new?Square(i?+?1);

}

System.out

.println("所有Square的總周長(zhǎng)是:"?+?Square.getTotalPerimeter(squares));

Square?sq1?=?new?Square(20);

Square?sq2?=?null;

try?{

sq2?=?(Square)?sq1.clone();

}?catch?(CloneNotSupportedException?e)?{

e.printStackTrace();

}

System.out.println("sq1"

+?(sq1.compareTo(sq2)?==?1???""

:?(sq1.compareTo(sq2)?==?0???"="?:?""))?+?"sq2");

}

}

class?Square?implements?Cloneable,?ComparableSquare?{

private?double?side;

public?Square(double?s1)?{

this.side?=?s1;

}

public?double?getSide()?{

return?side;

}

public?void?setSide(double?side)?{

this.side?=?side;

}

@Override

public?int?compareTo(Square?o)?{

if?(this.side??o.getSide())?{

return?1;

}?else?if?(this.side??o.getSide())?{

return?-1;

}?else?{

return?0;

}

}

@Override

protected?Object?clone()?throws?CloneNotSupportedException?{

return?super.clone();

}

public?double?getPerimeter()?{

return?side?*?4;

}

public?static?double?getTotalPerimeter(Square[]?squares)?{

double?totalPerimeter?=?0.0;

for?(int?i?=?0,?k?=?squares.length;?i??k;?i++)?{

totalPerimeter?+=?squares[i].getPerimeter();

}

return?totalPerimeter;

}

}

求java編程實(shí)現(xiàn)一個(gè)正方形放大縮小的代碼

package bdzhidao;

import java.awt.*;

import javax.swing.*;

public class Square extends JFrame{

public static void main(String[] args){

JFrame frame=new JFrame("可變正方形");

Spanel jp=new Spanel();

frame.add(jp);

frame.setSize(1366,768);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setResizable(true);

frame.setLocation(0,0);

frame.setVisible(true);

}

}

class Spanel extends JPanel{

int x=640;

int Width=8;

protected void paintComponent(Graphics g){

super.paintComponent(g);

g.setColor(new Color(10,200,40));

try{

Thread.sleep(1000);

}catch(InterruptedException e){

}

g.drawRect(x-=20,x-=20,Width+=10,Width+=10);

if(x=0){

System.exit(0);//當(dāng)正方形移到屏幕里面時(shí)關(guān)閉程序，如果沒(méi)有該語(yǔ)句則最后屏幕會(huì)變成綠色

}

repaint();

}

}

//縮小就只需要把相關(guān)數(shù)據(jù)更改一下就OK了，希望對(duì)你有幫助!

//其實(shí)就是利用線程不斷重新畫(huà)圖

java怎么繪制一個(gè)正方形？

可使用Graphics 的fillRect繪制正方形，代碼如下：

import?java.awt.Color;

import?java.awt.Graphics;

import?javax.swing.JFrame;

public?class?Rect?extends?JFrame{

Rect(){

setSize(300,?300);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);

}

public?void?paint(Graphics?g){

g.setColor(Color.blue);

g.drawRect(80,?80,?50,?50);

g.fillRect(150,?150,?50,?50);

}

public?static?void?main(String[]?args)?{

new?Rect();

}

}

怎么在java窗口中繪制一個(gè)正方體？該怎么寫(xiě)代碼

import?java.awt.Graphics;

import?javax.swing.JFrame;

public?class?aa?extends?JFrame?{

public?static?void?main(String[]?args)?{

new?aa();

}

public?aa()?{

this.pack();

this.setTitle("畫(huà)矩形");

this.setSize(300,?200);

this.setResizable(false);

this.setVisible(true);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

public?void?paint(Graphics?g)?{

this.setSize(300,?200);

g.drawRect(60,?60,?50,?30);

}

}