Question

本人初学java,希望各位高手帮一个忙：用java实现一个计算器，求代码尽量简单易懂；本人在此先谢过了！！！

Answer 1

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class CalculatorGUI {
private Frame f;
private Panel p1, p2;
private Button b0, b1, b2, b3, b4, b5, b6, b7, b8, b9;
private Button bPoint, bAdd, bDec, bMul, bDiv, bCal;
private TextField tf;
private String s, op;
private Calculator cal = new Calculator();
private boolean ifOp;

public CalculatorGUI() {
f = new Frame("Calculator");
p1 = new Panel();
p2 = new Panel();

b0 = new Button("0");
b1 = new Button("1");
b2 = new Button("2");
b3 = new Button("3");
b4 = new Button("4");
b5 = new Button("5");
b6 = new Button("6");
b7 = new Button("7");
b8 = new Button("8");
b9 = new Button("9");
bPoint = new Button(".");
bAdd = new Button("+");
bDec = new Button("-");
bMul = new Button("*");
bDiv = new Button("/");
bCal = new Button("=");

tf = new TextField(25);
tf.setEditable(false);

}

public void launchFrame() {
f.setSize(220, 160);
f.setResizable(false);
f.addWindowListener(new myWindowListener());
p1.setLayout(new FlowLayout(FlowLayout.CENTER));
p1.add(tf);
f.add(p1, BorderLayout.NORTH);
p2.setLayout(new GridLayout(4, 4));

b0.addActionListener(new setLabelText_ActionListener());
b1.addActionListener(new setLabelText_ActionListener());
b2.addActionListener(new setLabelText_ActionListener());
b3.addActionListener(new setLabelText_ActionListener());
b4.addActionListener(new setLabelText_ActionListener());
b5.addActionListener(new setLabelText_ActionListener());
b6.addActionListener(new setLabelText_ActionListener());
b7.addActionListener(new setLabelText_ActionListener());
b8.addActionListener(new setLabelText_ActionListener());
b9.addActionListener(new setLabelText_ActionListener());
bPoint.addActionListener(new setLabelText_ActionListener());
bAdd.addActionListener(new setOperator_ActionListener());
bDec.addActionListener(new setOperator_ActionListener());
bMul.addActionListener(new setOperator_ActionListener());
bDiv.addActionListener(new setOperator_ActionListener());
bCal.addActionListener(new setOperator_ActionListener());

p2.add(b7);
p2.add(b8);
p2.add(b9);
p2.add(bAdd);
p2.add(b4);
p2.add(b5);
p2.add(b6);
p2.add(bDec);
p2.add(b1);
p2.add(b2);
p2.add(b3);
p2.add(bMul);
p2.add(b0);
p2.add(bPoint);
p2.add(bCal);
p2.add(bDiv);
f.add(p2, BorderLayout.SOUTH);
f.setVisible(true);
}

public void setTextFieldText_Temp() {
if (tf.getText().length() < 15
&& (tf.getText().indexOf(".") == -1 || !s.equals("."))) {
tf.setText(tf.getText() + s);
} else {
tf.setText((tf.getText() + s).substring(0, 15));
}
}

public void setTextFieldText() {
if (ifOp) {
ifOp = false;
tf.setText("");
setTextFieldText_Temp();
} else {
setTextFieldText_Temp();
}
}

public static void main(String[] args) {
CalculatorGUI calculator = new CalculatorGUI();
calculator.launchFrame();
}

class myWindowListener extends WindowAdapter {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}

class setLabelText_ActionListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
Button tempB = (Button) e.getSource();
s = tempB.getLabel();
setTextFieldText();
}
}

class setOperator_ActionListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
Button tempB = (Button) e.getSource();
op = tempB.getLabel();
if (op.equals("+")) {
tf.setText(cal.opAdd(tf.getText()));
ifOp = true;
} else if (op.equals("-")) {
tf.setText(cal.opSubtract(tf.getText()));
ifOp = true;
} else if (op.equals("*")) {
tf.setText(cal.opMultiply(tf.getText()));
ifOp = true;
} else if (op.equals("/")) {
tf.setText(cal.opDivide(tf.getText()));
ifOp = true;
} else if (op.equals("=")) {
tf.setText(cal.opEquals(tf.getText()));
ifOp = true;
}
}
}

}

class Calculator {
private String result = "0";
private int op = 0, add = 1, sub = 2, mul = 3, div = 4;

private double stringToDouble(String x) {
double y = Double.parseDouble(x);
return y;
}

private void operate(String x) {
double x1 = stringToDouble(x);
double y = stringToDouble(result);
switch (op) {
case 0:
result = x;
break;
case 1:
result = String.valueOf(y + x1);
break;
case 2:
result = String.valueOf(y - x1);
break;
case 3:
result = String.valueOf(y * x1);
break;
case 4:
if (x1 != 0) {
result = String.valueOf(y / x1);
} else {
result = "The divisor can't be zero!";
}
break;
}
}

public String opAdd(String x) {
operate(x);
op = add;
return result;
}

public String opSubtract(String x) {
operate(x);
op = sub;
return result;
}

public String opMultiply(String x) {
operate(x);
op = mul;
return result;
}

public String opDivide(String x) {
operate(x);
op = div;
return result;
}

public String opEquals(String x) {
operate(x);
op = 0;
return result;
}

public void opClean() {
op = 0;
result = "0";
}
}

Answer 2

在这里我就说一句话：合适自己的，就是最好的。选择大于智慧，在很多的咨询者里，有不少的都是很关心这个学费的问题和就业率的问题，在这里我不敢说动力节点的学费是最便宜的，动力节点的就业率是百分之百的，但是我敢保证，交的那些学费是绝对划算的，就业率是达到百分之九十五以上的，“动力节点”或“王勇Java”成立于2009年，在成立初期从来都不招收零基础的学员，这样一时可以保证就业率，二是可以保证实用性，但是后来，越来越多没有基础的学生来咨询。所以，动力节点推出java基础班的培训，学费仅需200元，动力节点为什么敢收这么低的学费？这么低的学费能保证质量吗？我可以很确定的告诉大家，动力节点收这么低的学费是没有一分钱的利润，为的就是能让更多的java爱好者，能更好的更快的入门，为的就是让大家更确定..Y

Answer 3

现在学习Java的平台有很多，B站或者是腾讯课堂都是可以的，我们在B站分享了很多经典的Java基础视频教程，都是开源的，你可以去看看。