項目工程 實現四則運算的簡易計算器

1、/開發(fā)者：/簡介：實現四則運算的簡易計算器/ /*用swing圖形用戶界面實現計算器的設計*同時練習在線文檔注釋的使用方法* author linruier* version 1.0* since J2SE1.8*/import javax.swing.JButton;import java.awt.Graphics;import java.awt.FlowLayout;import javax.swing.JFrame;import javax.swing.JTextField;import java.awt.Color;import java.awt.Container;import ja

2、va.awt.Dimension;import javax.swing.JPanel;import java.awt.Font;import java.awt.event.ActionListener;import java.awt.event.ActionEvent;public class computer extends JFrame computer() super(簡易計算器); Font f = new Font(黑體, 30, 30); JTextField jt1 = new JTextField(null); JTextField jt2 = new JTextField(n

3、ull); jt1.setFont(f); jt2.setFont(f); jt1.setHorizontalAlignment(JTextField.RIGHT); jt2.setHorizontalAlignment(JTextField.RIGHT); Container c = getContentPane(); c.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5); c.add(jt1); c.add(jt2); jt1.setPreferredSize(new Dimension(370, 70); jt2.setPreferredSi

4、ze(new Dimension(370, 75); jt1.setEditable(false); jt2.setEditable(false); JButton jb = new JButton16; for (int j = 0; j 16; j+) jbj = new JButton(); jbj.setBackground(Color.WHITE); jbj.setFocusable(false); jbj.setPreferredSize(new Dimension(90, 90); jbj.setFont(f); c.add(jbj); this.setResizable(fal

5、se); /對各個按鈕的名稱賦值 jb0.setText(+); jb1.setText(-); jb2.setText(*); jb3.setText(/); jb4.setText(1); jb5.setText(2); jb6.setText(3); jb7.setText(C); jb7.setBackground(Color.ORANGE); jb8.setText(4); jb9.setText(5); jb10.setText(6); jb11.setText(0); jb12.setText(7); jb13.setText(8); jb14.setText(9); jb15.

6、setText(=); JButton Button_num = jb4, jb5, jb6, jb8, jb9, jb10, jb11, jb12, jb13, jb14 ; for (int i = 0; i Button_num.length; i+) Button_numi.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) JButton action_Button = (JButton) e.getSource(); jt2.setText(jt2.getText() +

7、 action_Button.getText(); ); for (int j = 0; j 4; j+) jbj.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) String s = jt2.getText(); char ch = s.charAt(s.length() - 1); if (ch = + | ch = - | ch = * | ch = /)(JButton) e.getSource().setEnabled(false); else jt1.setText(

8、jt2.getText(); jt2.setText(JButton) e.getSource().getText(); ); jb7.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) jt1.setText(null); jt2.setText(null); ); jb15.addActionListener(new ActionListener() public void actionPerformed(ActionEvent e) try String Calculate_S

9、tring = jt1.getText() + jt2.getText(); int result = calculation.result(Calculate_String); jt1.setText(null); jt2.setText(Integer.toString(result); catch(ArithmeticException ex) jt1.setText(null); jt2.setText(ERROR); ); public static void main(String args) computer app = new computer(); app.setDefaul

10、tCloseOperation(JFrame.EXIT_ON_CLOSE); app.setSize(400, 580); app.setVisible(true); /再定義一個計算類calculation.java:public class calculation calculation() ; boolean is_operator(char ch) if (ch = + | ch = - | ch = * | ch = /) return true; else return false; static int result(String s) String ch = +, -, *,

11、/ ; int i = 0; int index; while (s.indexOf(chi) = -1 & i 4) i+; if (i = 4) return - 1; else index = s.indexOf(chi); String s1 = s.substring(0, index); String s2 = s.substring(index + 1, s.length(); if (i = 0) return Integer.parseInt(s1) + Integer.parseInt(s2); if (i = 1) return Integer.parseInt(s1) - Integer.parseInt(s2); if (i = 2) return Integer.parseInt(s1) * Integer.parseInt(s2);