java计算器.doc

java计 算 器package jisuanqi;import java.awt.BorderLayout;import java.awt.Font;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.math.BigDecimal;import java.math.MathContext;import javax.swing.BoxLayout;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JTextField;public class Calculator implements ActionListenerprivate JFrame body;private JPanel head;private JPanel keys;private JTextField show;private JButton clearButton;public Calculator() body = new JFrame(计算器);head = new JPanel();keys = new JPanel();public void init() body.setLayout(new BorderLayout();head.setLayout(new BoxLayout(head,BoxLayout.X_AXIS);show = new JTextField(30);head.add(show);clearButton = new JButton(C);head.add(clearButton);body.add(head,BorderLayout.NORTH);keys.setLayout(new GridLayout(4,4,6,6);String str = 123+456-789*0.=/;for (int i = 0; i str.length(); i+) JButton key = new JButton(str.charAt(i)+);key.setFont(new Font(Courier New,Font.ROMAN_BASELINE,15);key.addActionListener(this);keys.add(key);body.add(keys,BorderLayout.SOUTH);public void setStyle() show.setText(0);show.setEditable(false);show.setHorizontalAlignment(JTextField.RIGHT);public void addEventHandler() clearButton.addActionListener(new ActionListener()public void actionPerformed(ActionEvent e) show.setText(0););public void showMe() init();setStyle();addEventHandler();body.pack();body.setLocation(200, 300);body.setResizable(false);body.setVisible(true);body.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);public void actionPerformed(ActionEvent e) String cmd = e.getActionCommand();String cmds = show.getText();String str = +-*/.;String temp = ;if (0.equals(cmds) & str.indexOf(cmd) = 0 & -.equals(cmd) = false) cmd = ;/对输入是 “*/.” 进心判断if (str.indexOf(cmd) = 0) if (-.equals(cmds) cmd = ;if (.equals(cmds) = false) & str.indexOf(cmds.charAt(cmds.length()-1) =0 ) cmd = ;/对输入是.进行判断if (.equals(cmd) for (int i = cmds.length()-1; i 0 ; i-) if (.equals(cmds.charAt(i)+) cmd = ;break;if (str.indexOf(cmds.charAt(i) = 0) break;if (cmds.indexOf(=) = 0) cmd = ;cmds = 0;/对输入是=进行判断if (=.equals(cmd) if (str.indexOf(cmds.charAt(cmds.length()-1) =0) cmd = ;if (0.equals(cmds) cmd = ;/实现算术表达式if (.equals(cmd) = false) temp = cmds;int i = 0;do if (*.equals(temp.charAt(i)+) | /.equals(temp.charAt(i)+) temp = f(temp,temp.charAt(i)+);i = 0;i+;System.out.println(temp);while(i temp.length();i = 0;do if (*.equals(temp.charAt(i)+) | /.equals(temp.charAt(i)+) temp = f(temp,temp.charAt(i)+);i = 0;if (+.equals(temp.charAt(i)+) | -.equals(temp.charAt(i)+) temp = f(temp,temp.charAt(i)+);i = 0;i+;System.out.println(temp);while(i temp.length();show.setText(cmds+cmd+temp);/算术表达式方法/s是表达式字符串，c是算术符public String f(String s,String c) String str = +-*/;String temp1 = ;String temp2 = ;for (int i = 0; i = 0; m-) if (str.indexOf(s.charAt(m) =0 ) break;temp1 += s.charAt(m);/字符串倒置String temp = ;for (int j = temp1.length()-1; j = 0 ; j-) temp += temp1.charAt(j);temp1 = temp;for (int m = i+1; m =0 ) break;temp2 += s.charAt(m);if (+.equals(c)s = s.replace(temp1+temp2, (new BigDecimal(temp1).add(new BigDecimal(temp2),MathContext.DECIMAL128).toString();if (-.equals(c)s = s.replace(temp1+-+temp2, (new BigDecimal(temp1).subtract(new BigDecimal(temp2),MathContext.DECIMAL128).toString();if (*.equals(c)s = s.replace(temp1+*+temp2, (new BigDecimal(temp1).multiply(new BigDecimal(temp2),MathContext.DECIMAL128).toString();if (/.equals(c)s = s.replace(temp1+/+temp