jisuanqi.zip_java 计算器 异常处理

//带界面的计算器应用程序 import java.awt.*; import java.awt.event.*; public class Counters extends Frame{ Panel panel; TextField tf; Button b[],add,sub,mul,div,cle, equ,dot,eight,sqr,tsex; Boolean isDot,operated,equaled; double storedNumber; char lastOperator; public Counters(){ isDot=false; operated=false; equaled=false; storedNumber=0; lastOperator='?'; panel=new Panel(); tf=new TextField(); b=new Button[10]; for(int i=0;i<10;i++){b[i]=new Button(""+i);} add=new Button("+"); sub=new Button("-"); mul=new Button("*"); div=new Button("/"); cle=new Button("Cle"); equ=new Button("="); dot=new Button("."); eight=new Button("N(8)"); sqr=new Button("√"); tsex=new Button("N(16)"); this.add(tf,BorderLayout.NORTH); this.add(panel,BorderLayout.CENTER); panel.setLayout(new GridLayout(5,4,10,10)); panel.add(b[1]); panel.add(b[2]); panel.add(b[3]); panel.add(add); panel.add(b[4]); panel.add(b[5]); panel.add(b[6]); panel.add(sub); panel.add(b[7]); panel.add(b[8]); panel.add(b[9]); panel.add(mul); panel.add(b[0]); panel.add(dot); panel.add(sqr); panel.add(div); panel.add(eight); panel.add(tsex); panel.add(cle); panel.add(equ); this.setTitle("计算器"); this.setSize(250,350); this.setVisible(true); for(int i=0;i<10;i++){b[i].addActionListener(new Monitor());} add.addActionListener(new Monitor()); sub.addActionListener(new Monitor()); mul.addActionListener(new Monitor()); div.addActionListener(new Monitor()); dot.addActionListener(new Monitor()); sqr.addActionListener(new Monitor()); equ.addActionListener(new Monitor()); cle.addActionListener(new Monitor()); this.addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0); } }); eight.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e){ int temp=Integer.parseInt(tf.getText()) ; tf.setText(""+Integer.toOctalString(temp)); } }); tsex.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e){ int temp=Integer.parseInt(tf.getText()); tf.setText(""+Integer.toHexString(temp)); } }); } class Monitor implements ActionListener{ public void actionPerformed(ActionEvent e){ Button btn=(Button)e.getSource(); if(btn==cle){ tf.setText("0"); isDot=false; storedNumber=0; lastOperator='?'; } else if(btn==equ){ operate('='); equaled=true; } else if(btn==add){ operate('+'); equaled=false; } else if(btn==sub){ operate('-'); equaled=false; } else if(btn==mul){ operate('*'); equaled=false; } else if(btn==div){ operate('/'); equaled=false; } else if(btn==sqr){ operate('s'); operate('='); equaled=true; } else{ if(equaled) storedNumber=0; for(int i=0;i<10;i++) if(btn==b[i]){ if(tf.getText().equals("0")) tf.setText(""+i); else if(!operated) tf.setText(tf.getText()+i); else{ tf.setText(""+i); operated=false; } } if(btn==dot&&!isDot){ tf.setText(tf.getText()+"."); isDot=true; } } } } public void operate(char operator){ double currentNumber = Double.valueOf(tf.getText()).doubleValue(); if (lastOperator == '?') storedNumber = currentNumber; else if (lastOperator == '+') storedNumber += currentNumber; else if (lastOperator == '-') storedNumber -= currentNumber; else if (lastOperator == '*') storedNumber *= currentNumber; else if (lastOperator == '/') storedNumber /= currentNumber; else if (lastOperator == 's') storedNumber = Math.sqrt(currentNumber); else if (lastOperator == '=' && equaled) storedNumber = currentNumber; tf.setText("" + storedNumber); operated = true; lastOperator = operator; } public static void main(String args[]){ new Counters(); } }