实现一个能够进行简单混合运算的计算器（要求对混合运算的表达式进行先乘除后加减运算）。其实现的效果如下图所示:
小练习。GUI窗体。
面向对象思路。
代码：
package 计算器;
import java.util.LinkedList;
public class Expression extends LinkedList<NumSign>
{
@Override
public String toString() {
String str="";
for(NumSign numSign:this)
{
str=str+numSign.getStrNum()+numSign.getSign();
}
return str;
}
public double calculate()
{
calMulAndDiv();
calAddAndSub();
return this.get(0).getNum();
}
private void calMulAndDiv()
{
for(int i=0;i<this.size();i++)
{
System.out.println(this.toString());
if(this.size()==1) return;
if(this.get(i).getSign()=='*')
{
double temp=this.get(i).getNum()*this.get(i+1).getNum();
this.get(i+1).setNum(temp);
this.remove(i);
i=-1;
continue;
}
if(this.get(i).getSign()=='/')
{
double temp=this.get(i).getNum()/this.get(i+1).getNum();
this.get(i+1).setNum(temp);
this.remove(i);
i=-1;
continue;
}
}
}
private void calAddAndSub()
{
for(int i=0;i<this.size();i++)
{
System.out.println(this.toString());
if(this.size()==1) return;
if(this.get(i).getSign()=='+')
{
double temp=this.get(i).getNum()+this.get(i+1).getNum();
this.get(i+1).setNum(temp);
this.remove(i);
i=-1;
continue;
}
if(this.get(i).getSign()=='-')
{
double temp=this.get(i).getNum()-this.get(i+1).getNum();
this.get(i+1).setNum(temp);
this.remove(i);
i=-1;
continue;
}
}
}
}
package 计算器;
public class NumSign {
private String strNum;
private char sign;
public NumSign() {
}
public NumSign(String strNum, char sign) {
this.strNum = strNum;
this.sign = sign;
}
public String getStrNum() {
return strNum;
}
public void setStrNum(String strNum) {
this.strNum = strNum;
}
public char getSign() {
return sign;
}
public void setSign(char sign) {
this.sign = sign;
}
public double getNum()
{
return Double.parseDouble(strNum);
}
public void setNum(double num)
{
this.strNum=String.valueOf(num);
}
}
package 计算器;
public class Main {
public static void main(String[] args) {
// TODO code application logic here
计算器JFrame jframe=new 计算器JFrame();
jframe.setVisible(true);
}
}
package 计算器;
public class 计算器JFrame extends javax.swing.JFrame {
Expression expression;
public 计算器JFrame() {
initComponents();
expression=new Expression();
}
/**
* 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() {
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();
jButton17 = new javax.swing.JButton();
jButton18 = new javax.swing.JButton();
jButton19 = new javax.swing.JButton();
jButton20 = new javax.swing.JButton();
jTextField1 = new javax.swing.JTextField();
jTextField2 = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setText("1");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("2");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jButton3.setText("3");
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
jButton4.setText("4");
jButton4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton4ActionPerformed(evt);
}
});
jButton5.setText("5");
jButton5.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton5ActionPerformed(evt);
}
});
jButton6.setText("6");
jButton6.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton6ActionPerformed(evt);
}
});
jButton7.setText("7");
jButton7.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton7ActionPerformed(evt);
}
});
jButton8.setText("8");
jButton8.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton8ActionPerformed(evt);
}
});
jButton9.setText("9");
jButton9.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton9ActionPerformed(evt);
}
});
jButton10.setText("0");
jButton10.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton10ActionPerformed(evt);
}
});
jButton11.setText(".");
jButton11.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton11ActionPerformed(evt);
}
});
jButton12.setText("=");
jButton12.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton12ActionPerformed(evt);
}
});
jButton13.setText("+");
jButton13.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton13ActionPerformed(evt);
}
});
jButton14.setText("-");
jButton14.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton14ActionPerformed(evt);
}
});
jButton15.setText("*");
jButton15.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton15ActionPerformed(evt);
}
});
jButton16.setText("/");
jButton16.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton16ActionPerformed(evt);
}
});
jButton17.setText("(");
jButton18.setText(")");
jButton19.setText("C");
jButton19.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton19ActionPerformed(evt);
}
});
jButton20.setText("Back");
jButton20.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton20ActionPerformed(evt);
}
});
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(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()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(jTextField2)
.addComponent(jTextField1, javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton10)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton11))
.addComponent(jButton8)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 41, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jButton7, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(18, 18, 18)
.addComponent(jButton5)))
.addGroup(layout.createSequentialGroup()
.addComponent(jButton17)
.addGap(18, 18, 18)
.addComponent(jButton18))))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createSequentialGroup()
.addComponent(jButton3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton14, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addComponent(jButton12)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton13, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jButton9)
.addComponent(jButton19))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jButton20, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton16, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))))
.addGroup(layout.createSequentialGroup()
.addGap(24, 24, 24)
.addComponent(jButton6)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton15, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE)))))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton17)
.addComponent(jButton18)
.addComponent(jButton19)
.addComponent(jButton20))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton7)
.addComponent(jButton8)
.addComponent(jButton9)
.addComponent(jButton16))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton4)
.addComponent(jButton5)
.addComponent(jButton15)
.addComponent(jButton6))
.addGap(10, 10, 10)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2)
.addComponent(jButton3)
.addComponent(jButton14))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton13)
.addComponent(jButton12)
.addComponent(jButton11)
.addComponent(jButton10))
.addGap(8, 8, 8))
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"1");
}
private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"4");
}
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"2");
}
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"3");
}
private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"5");
}
private void jButton6ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"6");
}
private void jButton7ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"7");
}
private void jButton8ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"8");
}
private void jButton9ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"9");
}
private void jButton10ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+"0");
}
private void jButton11ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText(this.jTextField1.getText()+".");
}
private void jButton12ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField2.setText("");
expression.add(new NumSign(this.jTextField1.getText(), '='));
String temp=this.expression.toString();
double result=this.expression.calculate();
this.jTextField2.setText(temp+result+"");
this.jTextField1.setText("");
this.expression.clear();
}
private void jButton13ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
expression.add(new NumSign(this.jTextField1.getText(), '+'));
this.jTextField1.setText("");
this.jTextField2.setText(this.expression.toString());
}
private void jButton14ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
expression.add(new NumSign(this.jTextField1.getText(), '-'));
this.jTextField1.setText("");
this.jTextField2.setText(this.expression.toString());
}
private void jButton15ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
expression.add(new NumSign(this.jTextField1.getText(), '*'));
this.jTextField1.setText("");
this.jTextField2.setText(this.expression.toString());
}
private void jButton16ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
expression.add(new NumSign(this.jTextField1.getText(), '/'));
this.jTextField1.setText("");
this.jTextField2.setText(this.expression.toString());
}
private void jButton20ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if(this.jTextField1.getText().length()>0)
this.jTextField1.setText(this.jTextField1.getText().substring(0, this.jTextField1.getText().length()-1));
}
private void jButton19ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.jTextField1.setText("");
this.jTextField2.setText("");
this.expression.clear();
}
/**
* @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(计算器JFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(计算器JFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(计算器JFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(计算器JFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new 计算器JFrame().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
}