Summary of common methods for writing calculators in Java
The examples in this article summarize common methods of writing calculators in Java. Share it with everyone for your reference, the details are as follows:
Method one:
package wanwa;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame {
private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
private JTextField displayField;// 计算结果显示区
private String lastCommand;// 保存+,-,*,/,=命令
private double result;// 保存计算结果
private boolean start;// 判断是否为数字的开始
public Calculator() {
super("Calculator");
container = getContentPane();
layout = new GridBagLayout();
container.setLayout(layout);
constraints = new GridBagConstraints();
start = true;
result = 0;
lastCommand = "=";
displayField = new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 4;
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 100;
constraints.weighty = 100;
layout.setConstraints(displayField, constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
// addButton("Backspace", 0, 1, 2, 1, insert);
// addButton("CE", 2, 1, 1, 1, insert);
// addButton("C", 3, 1, 1, 1, insert);
addButton("7", 0, 2, 1, 1, insert);
addButton("8", 1, 2, 1, 1, insert);
addButton("9", 2, 2, 1, 1, insert);
addButton("/", 3, 2, 1, 1, command);
addButton("4", 0, 3, 1, 1, insert);
addButton("5", 1, 3, 1, 1, insert);
addButton("6", 2, 3, 1, 1, insert);
addButton("*", 3, 3, 1, 1, command);
addButton("1", 0, 4, 1, 1, insert);
addButton("2", 1, 4, 1, 1, insert);
addButton("3", 2, 4, 1, 1, insert);
addButton("-", 3, 4, 1, 1, command);
addButton("0", 0, 5, 1, 1, insert);
// addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
addButton(".", 2, 5, 1, 1, insert);
addButton("+", 3, 5, 1, 1, command);
addButton("=", 0, 6, 4, 1, command);
this.setResizable(false);
setSize(180, 200);
setVisible(true);
}
private void addButton(String label, int row, int column, int with,
int height, ActionListener listener) {
JButton button = new JButton(label);
constraints.gridx = row;
constraints.gridy = column;
constraints.gridwidth = with;
constraints.gridheight = height;
constraints.fill = GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button, constraints);
container.add(button);
}
private class InsertAction implements ActionListener {
public void actionPerformed(ActionEvent event) {
String input = event.getActionCommand();
if (start) {
displayField.setText("");
start = false;
if (input.equals("+/-"))
displayField.setText(displayField.getText() + "-");
}
if (!input.equals("+/-")) {
if (input.equals("Backspace")) {
String str = displayField.getText();
if (str.length() > 0)
displayField.setText(str.substring(0, str.length() - 1));
} else if (input.equals("CE") || input.equals("C")) {
displayField.setText("0");
start = true;
} else
displayField.setText(displayField.getText() + input);
}
}
}
private class CommandAction implements ActionListener {
public void actionPerformed(ActionEvent evt) {
String command = evt.getActionCommand();
if (start) {
lastCommand = command;
} else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand = command;
start = true;
}
}
}
public void calculate(double x) {
if (lastCommand.equals("+"))
result += x;
else if (lastCommand.equals("-"))
result -= x;
else if (lastCommand.equals("*"))
result *= x;
else if (lastCommand.equals("/"))
result /= x;
else if (lastCommand.equals("="))
result = x;
displayField.setText("" + result);
}
public static void main(String[] args) {
Calculator calculator = new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}Copy after login
Copy after login
Method two:
import java.awt.*;
import java.awt.event.*;
public class MyCalculator {
PRivate Frame f;
private TextField tf = new TextField(30);
private long result;
private boolean append=false;
private char Operator='=';
private Button[] btn=new Button[15];
public MyCalculator() {
initComponent();
}
private void initComponent() {
f = new Frame("My Calculator V1.0");
f.setLayout(new BorderLayout()); //The frame uses BorderLayout
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent evt) {
System.exit(0);
}
});
Panel centerPanel = new Panel();
centerPanel.setLayout(new GridLayout(5, 3)); //The panel uses GridLayout
NumberListener nl=new NumberListener();
OperatorListener ol=new OperatorListener();
btn[10]=new Button("+");
btn[11]=new Button("-");
btn[12]=new Button("*");
btn[13]=new Button("/");
btn[14]=new Button("=");
for (int i=0;i<=9;i++){
btn[i]=new Button(String.valueOf(i));
centerPanel.add(btn[i]);
btn[i].addActionListener(nl);
if (i%2==1){
centerPanel.add(btn[(i+19)/2]);
btn[(i+19)/2].addActionListener(ol);
}
}
f.add(centerPanel, BorderLayout.CENTER);
Panel northPanel = new Panel();
tf.setEditable(false);
northPanel.add(tf);
f.add(northPanel, BorderLayout.NORTH);
}
public void go() {
f.pack();
f.setVisible(true);
}
public static void main(String[] args) {
new MyCalculator().go();
}
/**
*采用成员内部类方式，实现监听器接口，方便访问主类内类内部成员。
*此类负责数字按钮Action事件监听和处理
*/
class NumberListener implements ActionListener{
public void actionPerformed(ActionEvent e){
if (!append) {
tf.setText("");
append=true;
}
String s=tf.getText();
s+=e.getActionCommand();
tf.setText(s);
if (!btn[10].isEnabled()){
for(int i=10;i<=14;i++) btn[i].setEnabled(true);
}
}
}
/**
* 成员内部类，负责操作符按钮的事件处理
*/
class OperatorListener implements ActionListener{
public void actionPerformed(ActionEvent e){
if (!append) return;
for(int i=10;i<=14;i++) btn[i].setEnabled(false);
String s=tf.getText();
long num=Long.parseLong(s);//get the number of textfield
append=false; //set append
switch(operator){
case '+':result+=num;break;
case '-':result-=num;break;
case '*':result*=num;break;
case '/':{
if (num==0) result=0;
else result/=num;
break;
}
case '=':result=num;break;
}
tf.setText(String.valueOf(result));
//set the value of result to textfield
String op=e.getActionCommand();
operator=op.charAt(0); // set operator
}
}
}Copy after login
Method three:
package wanwa;
import java.util.*;
public class calc {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("*****************简易计算器****************");
System.out.println("*\t\t\t\t\t*");
System.out.println("* 使用说明： 1.加法 2.减法 3.乘法 4.除法 *");
System.out.println("*\t\t\t\t\t*");
System.out.println("*****************************************");
for(int i=0;i<100;i++){
System.out.print("\n请选择运算规则：");
int num = input.nextInt();
switch(num){
case 1:
System.out.println("\n******你选择了加法******\n");
System.out.print("请输入第1个加数:");
int jiashu1 = input.nextInt();
System.out.print("请输入第2个加数:");
int jiashu2 = input.nextInt();
System.out.println("运算结果为:" + jiashu1 + " + " + jiashu1 + " = " + (jiashu1 + jiashu2));
break;
case 2:
System.out.println("\n******你选择了减法******\n");
System.out.print("请输入被减数:");
int jianshu1 = input.nextInt();
System.out.print("请输入减数:");
int jianshu2 = input.nextInt();
System.out.println("运算结果为:" + jianshu1 + " - " + jianshu2 + " = " + (jianshu1 - jianshu2));
break;
case 3:
System.out.println("\n******你选择了乘法******\n");
System.out.print("请输入第1个因数:");
int chengfa1 = input.nextInt();
System.out.print("请输入第2个因数:");
int chengfa2 = input.nextInt();
System.out.println("运算结果为:" + chengfa1 + " * " + chengfa2 + " = " + (chengfa1 * chengfa2));
break;
case 4:
System.out.println("\n******你选择了除法******\n");
System.out.print("请输入被除数:");
double chufa1 = input.nextInt();
System.out.print("请输入除数:");
double chufa2 = input.nextInt();
System.out.println("运算结果为:" + chufa1 + " / " + chufa2 + " = " + (chufa1 / chufa2) + " 余 " + (chufa1 % chufa2));
break;
default:
System.out.println("\n你的选择有错，请重新选择!");
break;
}
}
}
}Copy after login
Method four:
package wanwa;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame {
private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
private JTextField displayField;// 计算结果显示区
private String lastCommand;// 保存+,-,*,/,=命令
private double result;// 保存计算结果
private boolean start;// 判断是否为数字的开始
public Calculator() {
super("Calculator");
container = getContentPane();
layout = new GridBagLayout();
container.setLayout(layout);
constraints = new GridBagConstraints();
start = true;
result = 0;
lastCommand = "=";
displayField = new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 4;
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 100;
constraints.weighty = 100;
layout.setConstraints(displayField, constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
// addButton("Backspace", 0, 1, 2, 1, insert);
// addButton("CE", 2, 1, 1, 1, insert);
// addButton("C", 3, 1, 1, 1, insert);
addButton("7", 0, 2, 1, 1, insert);
addButton("8", 1, 2, 1, 1, insert);
addButton("9", 2, 2, 1, 1, insert);
addButton("/", 3, 2, 1, 1, command);
addButton("4", 0, 3, 1, 1, insert);
addButton("5", 1, 3, 1, 1, insert);
addButton("6", 2, 3, 1, 1, insert);
addButton("*", 3, 3, 1, 1, command);
addButton("1", 0, 4, 1, 1, insert);
addButton("2", 1, 4, 1, 1, insert);
addButton("3", 2, 4, 1, 1, insert);
addButton("-", 3, 4, 1, 1, command);
addButton("0", 0, 5, 1, 1, insert);
// addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
addButton(".", 2, 5, 1, 1, insert);
addButton("+", 3, 5, 1, 1, command);
addButton("=", 0, 6, 4, 1, command);
this.setResizable(false);
setSize(180, 200);
setVisible(true);
}
private void addButton(String label, int row, int column, int with,
int height, ActionListener listener) {
JButton button = new JButton(label);
constraints.gridx = row;
constraints.gridy = column;
constraints.gridwidth = with;
constraints.gridheight = height;
constraints.fill = GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button, constraints);
container.add(button);
}
private class InsertAction implements ActionListener {
public void actionPerformed(ActionEvent event) {
String input = event.getActionCommand();
if (start) {
displayField.setText("");
start = false;
if (input.equals("+/-"))
displayField.setText(displayField.getText() + "-");
}
if (!input.equals("+/-")) {
if (input.equals("Backspace")) {
String str = displayField.getText();
if (str.length() > 0)
displayField.setText(str.substring(0, str.length() - 1));
} else if (input.equals("CE") || input.equals("C")) {
displayField.setText("0");
start = true;
} else
displayField.setText(displayField.getText() + input);
}
}
}
private class CommandAction implements ActionListener {
public void actionPerformed(ActionEvent evt) {
String command = evt.getActionCommand();
if (start) {
lastCommand = command;
} else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand = command;
start = true;
}
}
}
public void calculate(double x) {
if (lastCommand.equals("+"))
result += x;
else if (lastCommand.equals("-"))
result -= x;
else if (lastCommand.equals("*"))
result *= x;
else if (lastCommand.equals("/"))
result /= x;
else if (lastCommand.equals("="))
result = x;
displayField.setText("" + result);
}
public static void main(String[] args) {
Calculator calculator = new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}Copy after login
Copy after login
I hope this article will be helpful to everyone in Java programming.
For more examples and summary of common methods of writing calculators in Java, please pay attention to the PHP Chinese website for related articles!
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Assassin's Creed Shadows: Seashell Riddle Solution
3 weeks ago
By DDD
What's New in Windows 11 KB5054979 & How to Fix Update Issues
2 weeks ago
By DDD
Where to find the Crane Control Keycard in Atomfall
3 weeks ago
By DDD
Assassin's Creed Shadows - How To Find The Blacksmith And Unlock Weapon And Armour Customisation
1 months ago
By DDD
Roblox: Dead Rails - How To Complete Every Challenge
3 weeks ago
By DDD
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
CakePHP Tutorial
1387
52
1387
52
How to simplify field mapping issues in system docking using MapStruct?
Apr 19, 2025 pm 06:21 PM
Field mapping processing in system docking often encounters a difficult problem when performing system docking: how to effectively map the interface fields of system A...
How to elegantly obtain entity class variable names to build database query conditions?
Apr 19, 2025 pm 11:42 PM
When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...
What is the difference between memory leaks in Java programs on ARM and x86 architecture CPUs?
Apr 19, 2025 pm 11:18 PM
Analysis of memory leak phenomenon of Java programs on different architecture CPUs. This article will discuss a case where a Java program exhibits different memory behaviors on ARM and x86 architecture CPUs...
How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?
Apr 19, 2025 pm 11:45 PM
Start Spring using IntelliJIDEAUltimate version...
In Java remote debugging, how to correctly obtain constant values on remote servers?
Apr 19, 2025 pm 01:54 PM
Questions and Answers about constant acquisition in Java Remote Debugging When using Java for remote debugging, many developers may encounter some difficult phenomena. It...
Is the company's security software causing the application to fail to run? How to troubleshoot and solve it?
Apr 19, 2025 pm 04:51 PM
Troubleshooting and solutions to the company's security software that causes some applications to not function properly. Many companies will deploy security software in order to ensure internal network security. ...
How to correctly divide business logic and non-business logic in hierarchical architecture in back-end development?
Apr 19, 2025 pm 07:15 PM
Discussing the hierarchical architecture problem in back-end development. In back-end development, common hierarchical architectures include controller, service and dao...
How to convert names to numbers to implement sorting within groups?
Apr 19, 2025 pm 01:57 PM
How to convert names to numbers to implement sorting within groups? When sorting users in groups, it is often necessary to convert the user's name into numbers so that it can be different...
