用java写一个简单的计算器详解代码

使用java实现一个能进行整行读取并计算的简易计算器

下面计算器的界面：



以及具体的计算形式：



下面是Jisuanapp类的代码：

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package jisuanapp;

/**
*
* @author Administrator
*/
public class Jisuanapp {

/**
* @param args the command line arguments
*/
public static void main(String[] args) {
jiemian jiem = new jiemian();
jiem.setTitle("简单的计算器");
jiem.setVisible(true);

}

}


下面是Calculation类的具体代码：

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package jisuanapp;

import java.util.ArrayList;
import java.util.Stack;
import java.math.BigDecimal;
/**
*
* @author Administrator
*/
public class Calculation {

public double calculate(String copy)
{
char []calculate = copy.toCharArray();
int sum=0;
for(int i=0;i<calculate.length;i++)
{
if((calculate[i]<'0'||calculate[i]>'9')&&calculate[i]!='.')
sum++;
}
sum*=2;
sum++;

return(results(sum, copy));
}

public static double add(double v1,double v2){
BigDecimal b1 = new BigDecimal(Double.toString(v1));
BigDecimal b2 = new BigDecimal(Double.toString(v2));
return b1.add(b2).doubleValue();
}

public double results(int longs,String str)
{
char []calculate = str.toCharArray();
String [] zong = new String[longs];
int startt=0,endd=0,num=0;
for(int i =0;i<calculate.length;i++)
{
if((calculate[i]<'0'||calculate[i]>'9')&&calculate[i]!='.')
{
endd=i;
zong[num++] = str.substring(startt, endd);
startt = endd;
endd++;
zong[num++] = str.substring(startt, endd);
startt = i+1;
}
}
zong[num] = str.substring(startt, calculate.length);
Stack<Double> s = new Stack<Double>();
double m = Double.parseDouble(zong[0]);
s.push(m);
for(int i=1;i<=num;i++)
{
if(i%2==1)
{
if(zong[i].compareTo("+")==0)
{
double h = Double.parseDouble(zong[i+1]);
s.push(h);
}
if(zong[i].compareTo("-")==0)
{
double h = Double.parseDouble(zong[i+1]);
s.push(-h);
}
if(zong[i].compareTo("*")==0)
{
double h = Double.parseDouble(zong[i+1]);
double sign = s.peek();
s.pop();
sign *= h;
s.push(sign);
}
if(zong[i].compareTo("/")==0)
{
double h = Double.parseDouble(zong[i+1]);
double sign = s.peek();
s.pop();
sign /= h;
s.push(sign);
}
}
}
double sum = 0,result = 0;
while(!s.empty())
{
result = add(sum, s.peek());
sum = result;
s.pop();
}
return sum;
}

}


下面是JFrame界面的具体代码：

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package jisuanapp;

import javax.swing.JTextField;

/**
*
* @author Administrator
*/
public class jiemian extends javax.swing.JFrame {

/**
* Creates new form jiemian
*/
public jiemian() {
initComponents();
}

/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

jTextField1 = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jButton4 = new javax.swing.JButton();
jButton5 = new javax.swing.JButton();
jButton6 = new javax.swing.JButton();
jButton7 = new javax.swing.JButton();
jButton8 = new javax.swing.JButton();
jButton9 = new javax.swing.JButton();
jButton10 = new javax.swing.JButton();
jButton11 = new javax.swing.JButton();
jButton12 = new javax.swing.JButton();
jButton13 = new javax.swing.JButton();
jButton14 = new javax.swing.JButton();
jButton15 = new javax.swing.JButton();
jButton16 = new javax.swing.JButton();
jButton19 = new javax.swing.JButton();
jButton20 = new javax.swing.JButton();
jTextField2 = new javax.swing.JTextField();
jButton17 = new javax.swing.JButton();
jButton18 = new javax.swing.JButton();

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setPreferredSize(new java.awt.Dimension(450, 500));

jTextField1.setToolTipText("");
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(evt);
}
});

jButton1.setText("1");
jButton1.setPreferredSize(new java.awt.Dimension(90, 50));
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});

jButton2.setText("2");
jButton2.setPreferredSize(new java.awt.Dimension(90, 50));
jButton2.addActionListener(new java.awt.event.ActionListener() {

4000
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});

jButton3.setText("3");
jButton3.setPreferredSize(new java.awt.Dimension(90, 50));
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});

jButton4.setText("4");
jButton4.setPreferredSize(new java.awt.Dimension(90, 50));
jButton4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton4ActionPerformed(evt);
}
});

jButton5.setText("5");
jButton5.setPreferredSize(new java.awt.Dimension(90, 50));
jButton5.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton5ActionPerformed(evt);
}
});

jButton6.setText("6");
jButton6.setPreferredSize(new java.awt.Dimension(90, 50));
jButton6.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton6ActionPerformed(evt);
}
});

jButton7.setText("7");
jButton7.setPreferredSize(new java.awt.Dimension(90, 50));
jButton7.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton7ActionPerformed(evt);
}
});

jButton8.setText("8");
jButton8.setPreferredSize(new java.awt.Dimension(90, 50));
jButton8.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton8ActionPerformed(evt);
}
});

jButton9.setText("9");
jButton9.setPreferredSize(new java.awt.Dimension(90, 50));
jButton9.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton9ActionPerformed(evt);
}
});

jButton10.setText("0");
jButton10.setPreferredSize(new java.awt.Dimension(90, 50));
jButton10.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton10ActionPerformed(evt);
}
});

jButton11.setText("+");
jButton11.setPreferredSize(new java.awt.Dimension(90, 50));
jButton11.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton11ActionPerformed(evt);
}
});

jButton12.setText("-");
jButton12.setPreferredSize(new java.awt.Dimension(90, 50));
jButton12.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton12ActionPerformed(evt);
}
});

jButton13.setText("*");
jButton13.setPreferredSize(new java.awt.Dimension(90, 50));
jButton13.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton13ActionPerformed(evt);
}
});

jButton14.setText("/");
jButton14.setPreferredSize(new java.awt.Dimension(90, 50));
jButton14.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton14ActionPerformed(evt);
}
});

jButton15.setText("←");
jButton15.setPreferredSize(new java.awt.Dimension(90, 50));
jButton15.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton15ActionPerformed(evt);
}
});

jButton16.setText("C");
jButton16.setPreferredSize(new java.awt.Dimension(90, 50));
jButton16.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton16ActionPerformed(evt);
}
});

jButton19.setText(".");
jButton19.setPreferredSize(new java.awt.Dimension(90, 50));
jButton19.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton19ActionPerformed(evt);
}
});

jButton20.setText("=");
jButton20.setPreferredSize(new java.awt.Dimension(90, 50));
jButton20.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton20ActionPerformed(evt);
}
});

jTextField2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField2ActionPerformed(evt);
}
});

jButton17.setText("AC");
jButton17.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton17ActionPerformed(evt);
}
});

jButton18.setText("new");
jButton18.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton18ActionPerformed(evt);
}
});

javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(30, 30, 30)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton8, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton9, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton13, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton11, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jButton6, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton12, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addComponent(jTextField1)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 378, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(jButton17, javax.swing.GroupLayout.PREFERRED_SIZE, 90, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton16, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton15, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton14, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGroup(layout.createSequentialGroup()
.addComponent(jButton18, javax.swing.GroupLayout.PREFERRED_SIZE, 91, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton10, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton19, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton20, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(1281, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(25, 25, 25)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton14, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton15, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton16, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addComponent(jButton17, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton7, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton8, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton9, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton13, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton6, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton4, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton12, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton11, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)

c0c7
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton10, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton19, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jButton20, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addComponent(jButton18, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addContainerGap(362, Short.MAX_VALUE))
);

pack();
}// </editor-fold>

private int flag = 1;
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "1");
}

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "2");
}

private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "3");
}

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "4");
}

private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "5");
}

private void jButton6ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "6");
}

private void jButton7ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "7");
}

private void jButton8ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "8");
}

private void jButton9ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "9");
}

private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField1.getText() + "0");
}

private void jButton11ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
char []calculate = jTextField1.getText().toCharArray();
char num = calculate[calculate.length - 1];
if(num>='0'&&num<='9')
{
jTextField1.setText(jTextField1.getText() + "+");
this.flag = 1;
}
}
}

private void jButton12ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
char []calculate = jTextField1.getText().toCharArray();
char num = calculate[calculate.length - 1];
if(num>='0'&&num<='9')
{
jTextField1.setText(jTextField1.getText() + "-");
this.flag = 1;
}
}
}

private void jButton13ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
char []calculate = jTextField1.getText().toCharArray();
char num = calculate[calculate.length - 1];
if(num>='0'&&num<='9')
{
jTextField1.setText(jTextField1.getText() + "*");
this.flag = 1;
}
}
}

private void jButton14ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
char []calculate = jTextField1.getText().toCharArray();
char num = calculate[calculate.length - 1];
if(num>='0'&&num<='9')
{
jTextField1.setText(jTextField1.getText() + "/");
this.flag = 1;
}
}
}

public String getjTextField1() {
return jTextField1.getText();
}

private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {

}

private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
Calculation ji = new Calculation();
double sum = ji.calculate(jTextField1.getText());
jTextField2.setText(Double.toString(sum));
}
}

private void jButton15ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
if(jTextField1.getText().substring(jTextField1.getText().length()-1,jTextField1.getText().length()).compareTo(".") == 0)
flag = 1;
jTextField1.setText(jTextField1.getText().substring(0,jTextField1.getText().length() -1));
}
}

private void jButton16ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText("");
flag = 1;
}

private void jButton19ActionPerformed(java.awt.event.ActionEvent evt) {
if(jTextField1.getText().compareTo("")!=0)
{
char []calculate = jTextField1.getText().toCharArray();
char num = calculate[calculate.length - 1];
if(num>='0'&&num<='9'&&this.flag == 1)
{
jTextField1.setText(jTextField1.getText() + ".");
this.flag = 0;
}
}
}

private void jTextField2ActionPerformed(java.awt.event.ActionEvent evt) {

}

private void jButton17ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText("");
jTextField2.setText("");
flag = 1;
}

private void jButton18ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText(jTextField2.getText());
flag = 0;
jTextField2.setText("");
}

/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html */
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(jiemian.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(jiemian.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(jiemian.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(jiemian.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>

/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new jiemian().setVisible(true);
}
});
}

// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton10;
private javax.swing.JButton jButton11;
private javax.swing.JButton jButton12;
private javax.swing.JButton jButton13;
private javax.swing.JButton jButton14;
private javax.swing.JButton jButton15;
private javax.swing.JButton jButton16;
private javax.swing.JButton jButton17;
private javax.swing.JButton jButton18;
private javax.swing.JButton jButton19;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton20;
private javax.swing.JButton jButton3;
private javax.swing.JButton jButton4;
private javax.swing.JButton jButton5;
private javax.swing.JButton jButton6;
private javax.swing.JButton jButton7;
private javax.swing.JButton jButton8;
private javax.swing.JButton jButton9;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
// End of variables declaration
}