package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.HashMap;
import java.util.Stack;
/**
* Created by zxx on 2020/10/15.
*/
public class Calculator extends JFrame{
private Stack<Double> operandStack= new Stack<>();
private Stack<String> operatorStack = new Stack<>();
private Calculator(){
setTitle("计算器");
setSize(266,340);
//setSize(400,540);
Container c=getContentPane();
c.setLayout(null);
JTextArea jt=new JTextArea(100,100);
jt.setFont(new Font("Aria",Font.BOLD,32));
jt.setLineWrap(true);
JScrollPane sp=new JScrollPane(jt);
jt.setCaretPosition(jt.getDocument().getLength());
sp.setBounds(0,0,250,100);
c.add(sp);
JPanel p=new JPanel();
p.setLayout(new GridLayout(5,4,0,0));
p.setBounds(0,100,250,200);
String[] num={"(",")","AC","/","7","8","9","*","4","5","6","-","1","2","3","+","0",".","DEL","="};
JButton[] jb=new JButton[20];
for(int i=0;i<20;i ++ ){
jb[i]=new JButton(num[i]);
p.add(jb[i]);
}
c.add(p);
for(int i=0;i<18;i ++){
if(i!=2){
final int j=i;
jb[i].addActionListener(e-> jt.append(num[j]));
}
}
jb[2].addActionListener(e->{
jt.setText("");
operandStack.clear();
operatorStack.clear();
});
jb[18].addActionListener(e->{
try{
jt.setText(jt.getText().substring(0,jt.getText().length()-1));
}catch(Exception ignored) { }//忽略这个异常 IDEA就是好用！！！
});
jb[19].addActionListener(e->{
try{
double x= calculate(jt.getText()+ "#");
jt.setText("");
jt.append(String.valueOf(x));
}catch(Exception ex){
if(ex.getMessage()==null)
jt.setText("ERROR!");
else
jt.setText(ex.getMessage());
}
});
//禁止文本域的enter换行
KeyStroke enter = KeyStroke.getKeyStroke("ENTER");
jt.getInputMap().put(enter, "none");
this.getRootPane().setDefaultButton(jb[19]);
c.addKeyListener(new KeyAdapter() {
@Override
public void keyTyped(KeyEvent e)
{
}
public void keyPressed(KeyEvent e) //键盘按键监听
{
char label=e.getKeyChar();
String k=String.valueOf(label);
if(label==KeyEvent.VK_ENTER)
{
calculate();
}
else if(label==KeyEvent.VK_BACK_SPACE)
{
String s = jt.getText();
if(s!=null)
{
calculate(); //调用定义的处理←方法
}else
{
jt.setText(s);
}
}
else
{
calculate(k); //按下数字和运算符号的叠加
}
}
public void keyReleased(KeyEvent e)
{
}
});
setVisible(true);
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
private void calculate(){
String b = operatorStack.pop();
double c = operandStack.pop();
double d = operandStack.pop();
double e;
if (b.equals("+")) {
e = d + c;
operandStack.push(e);
}
if (b.equals("-")) {
e = d - c;
operandStack.push(e);
}
if (b.equals("*")) {
e = d * c;
operandStack.push(e);
}
if (b.equals("/")) {
if(c==0)
throw new ArithmeticException("DivideByZero!");//不可修改为Exception
// Exception的异常是必须处理的,是受控异常;而ArithmeticException 不是必须处理的 ,受控异常必须强制处理
e = d / c;
operandStack.push(e);
}
}
private Double calculate(String text){
HashMap<String,Integer> precede=new HashMap<>();
precede.put("(",0);
precede.put(")",0);
precede.put("/",2);
precede.put("*",2);
precede.put("-",1);
precede.put("+",1);
precede.put("#",0);
operatorStack.push("#");
int flag=0;
for(int i=0;i<text.length();i++ ){
String a=String.valueOf(text.charAt(i));
if(!a.matches("[0-9.]")){
if(flag!=i)
operandStack.push(Double.parseDouble(text.substring(flag,i)));
flag=i+ 1;
while(!(a.equals("#")&&operatorStack.peek().equals("#"))){
if(precede.get(a)>precede.get(operatorStack.peek())||a.equals("(")){
operatorStack.push(a);
break;
}else {
if(a.equals(")")) {
while(!operatorStack.peek().equals("("))
calculate();
operatorStack.pop();
break;
}
calculate();
}
}
}
}
return(operandStack.pop());
}
public static void main(String[] args){
new Calculator();
}
}