package chp13;
import java.util.*;
import java.util.Stack;
import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.RenderingHints.Key;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.beans.Expression;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.*;
public class Exercise13_05 extends JFrame implements KeyListener, ActionListener {
JTextField text;
String display;
boolean flag=false;
void init()
{
setTitle("计算器示例");
text=new JTextField("0.0");
text.setEditable(false);
text.setHorizontalAlignment(JTextField.RIGHT);//居右显示
add(text, BorderLayout.NORTH);
text.addKeyListener(this);
JPanel p = new JPanel();//设置一个JPanel容器对象
GridBagLayout layout = new GridBagLayout();
p.setLayout(layout);
String[] name = {"C","←","*","÷","7","8","9","-","4","5","6","+","1","2","3","=","0","."};
JButton [] button=new JButton[name.length];
for (int i = 0; i < name.length; ++i)
{
button[i]=new JButton(name[i]);
button[i].setActionCommand(name[i]);
button[i].addActionListener(this);
//button[i].addKeyListener(this);
}
GridBagConstraints s= new GridBagConstraints();//定义一个GridBagConstraints，
s.fill = GridBagConstraints.BOTH;//使组件充满显示区域
for(int i=1;i<16;i++)
{
if(i%4!=0)
s.gridwidth=1;//设置组件水平所占用的网格数，如果为0，组件是该行的最后一个
else
s.gridwidth=0;
s.weightx = 1;//设置组件水平的拉伸幅度，为0不拉伸，不为0就随着窗口增大进行拉伸
s.weighty=1;//设置组件垂直的拉伸幅度，为0不拉伸，不为0就随着窗口增大进行拉伸
p.add(button[i-1],s);//将生成的按钮按照GridBagConstraints设置位置进行添加
}
s.gridwidth=0;
s.gridheight=2;
s.weightx = 1;
s.weighty=1;
p.add(button[15],s);//将“=”按钮设置为占用两行一列
s.gridx=0;
s.gridy=4;
s.gridheight=1;
s.gridwidth=2;
s.weightx = 1;
s.weighty=1;
p.add(button[16],s);//将“0”按钮设置在第4行，第0列显示，并占用两列一行，添加入面板
s.gridx=2;
s.gridy=4;
s.gridwidth=1;
s.gridheight=1;
s.weightx = 0;
s.weighty=0;
p.add(button[17],s);//将“.”按钮设置在第4行，第2列显示，添加入面板
add(p);//将JPanel容器加入到窗口中，默认为中间位置
setSize(250,250);//设置窗口大小为250*250
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e) {
if (flag==true){
text.setText("0.0");
flag=false;
}
String content=text.getText();
if(!content.equals("0.0")){//计算器为非初始状态
if(e.getActionCommand().equals("C")){//如果计算器清零
text.setText("0.0");
}
else
{
if((e.getActionCommand().equals("←"))){//删除字符串最后一个字符
if(content.length()>1)
text.setText(content.substring(0, content.length()-1));
else
text.setText("0.0");
}
else
{//输入任意字符
Pattern pattern=Pattern.compile("\d$");
Matcher matcher=pattern.matcher(content);
if(matcher.find()){//如果字符串最后是数字，可以输入任何信息
//text.setText(content+e.getActionCommand());
if(e.getActionCommand().equals("=")){
String name=text.getText();
calculate expression = new calculate(name+"#");
expression.solve();
double result = expression.operate();
text.setText(String.valueOf(result));
flag=true;
}
else{
text.setText(content+e.getActionCommand());
}
}
else{//否则只能输入数字
java语言基础篇课后答案在哪找 matcher=pattern.matcher(e.getActionCommand());
if(matcher.find()){//如果是数字，可以输入
text.setText(content+e.getActionCommand());
}
}
}
}
}
else{
Pattern pattern=Pattern.compile("\d$");
Matcher matcher=pattern.matcher(e.getActionCommand());
if(matcher.find()){
text.setText(e.getActionCommand());
}
}
}
public void keyTyped(KeyEvent e) {}
public void keyPressed(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}
public static void main(String s[]){
new Exercise13_05().init();
}
}
class calculate {
Stack<Character> stack = new Stack<Character>();
char a[]=new char[100];
char b[]=new char[100];// 后缀表达式
public calculate(String in){
this.a = in.toCharArray();
solve();
}
public int priority(char operator){
switch (operator) {//运算符优先级
case '+':
return 1;
case '-':
return 1;
case '*':
return 2;
case '÷':
return 2;
case '(':
return 0;
default:
return -1;
}
}
public void solve() {//字符串解析
stack.push('#');
int la = a.length;
int j = 0;
boolean flag = true;//有数字
for(int i = 0;i < la;i++){
if(a[i] >= '0' && a[i] <= '9' || a[i] == '.'){
b[j++] = a[i];
flag = true;
}
else if(a[i] == '('){
stack.push(a[i]);
}
else if(a[i] == ')'){
if(flag == true){
b[j++] = ' ';
flag = false;
}
while(stack.peek() !='('){
b[j++]=stack.peek();
stack.pop();
}
stack.pop();
}
else{
if(flag == true){
b[j++] = ' ';
flag = false;
}
while( priority(stack.peek()) >= priority(a[i]) && stack.peek() != '#'){
b[j++] = stack.peek();
stack.pop();
}
stack.push(a[i]);
}
}
while(stack.peek() != '#'){
b[j++] = stack.peek();
stack.pop();
}
b[j] = '
';
}
public double operate() {
double res = 0;
double sum = 0;
int position = 0;
boolean xiaoshu = false;
double dianwei = 0.1;
Stack<Double> stack_operate = new Stack<Double>();
while(b[position] != '
'){
if(b[position] >= '0' && b[position] <='9'){
if(xiaoshu == false) res = res*10+b[position]-'0';
else{
res = res+dianwei*(b[position]-'0');
dianwei = dianwei*0.1;
}
}
else if(b[position] == '.'){
xiaoshu = true;
}
else if(b[position] == ' '){
xiaoshu = false;
dianwei = 0.1;
if(res != 0){
stack_operate.push(res);
res = 0;
}
}
else{
double x1 = stack_operate.peek();
stack_operate.pop();
double x2 = stack_operate.peek();
stack_operate.pop();
if(b[position] == '+') sum = x1+x2;
else if(b[position] == '-') sum = x2-x1;
else if(b[position] == '*') sum = x2*x1;
else if (b[position] == '÷') sum = x2/x1;
stack_operate.push(sum);
res = 0;
}
position++;
}
return sum;
}
版权声明：
本文来源网络，所有图片文章版权属于原作者，如有侵权，联系删除。
本文网址：https://www.bianchenghao6.com/h6javajc/20669.html