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Java编写计算器的常见方法实例总结

2016-7-29 15:41| 发布者: zhangjf| 查看: 486| 评论: 0

摘要: 本文实例总结了Java编写计算器的常见方法。分享给大家供大家参考，具体如下： 方法一： package wanwa;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Calculator extends JFrame {p ...

本文实例总结了Java编写计算器的常见方法。分享给大家供大家参考，具体如下：

方法一：

  2. package wanwa;
  3. import java.awt.*;
  4. import java.awt.event.*;
  5. import javax.swing.*;
  6. public class Calculator extends JFrame {
  7. private Container container;
  8. private GridBagLayout layout;
  9. private GridBagConstraints constraints;
  10. private JTextField displayField;// 计算结果显示区
  11. private String lastCommand;// 保存+,-,*,/,=命令
  12. private double result;// 保存计算结果
  13. private boolean start;// 判断是否为数字的开始
  14. public Calculator() {
  15. super("Calculator");
  16. container = getContentPane();
  17. layout = new GridBagLayout();
  18. container.setLayout(layout);
  19. constraints = new GridBagConstraints();
  20. start = true;
  21. result = 0;
  22. lastCommand = "=";
  23. displayField = new JTextField(20);
  24. displayField.setHorizontalAlignment(JTextField.RIGHT);
  25. constraints.gridx = 0;
  26. constraints.gridy = 0;
  27. constraints.gridwidth = 4;
  28. constraints.gridheight = 1;
  29. constraints.fill = GridBagConstraints.BOTH;
  30. constraints.weightx = 100;
  31. constraints.weighty = 100;
  32. layout.setConstraints(displayField, constraints);
  33. container.add(displayField);
  34. ActionListener insert = new InsertAction();
  35. ActionListener command = new CommandAction();
  36. // addButton("Backspace", 0, 1, 2, 1, insert);
  37. // addButton("CE", 2, 1, 1, 1, insert);
  38. // addButton("C", 3, 1, 1, 1, insert);
  39. addButton("7", 0, 2, 1, 1, insert);
  40. addButton("8", 1, 2, 1, 1, insert);
  41. addButton("9", 2, 2, 1, 1, insert);
  42. addButton("/", 3, 2, 1, 1, command);
  43. addButton("4", 0, 3, 1, 1, insert);
  44. addButton("5", 1, 3, 1, 1, insert);
  45. addButton("6", 2, 3, 1, 1, insert);
  46. addButton("*", 3, 3, 1, 1, command);
  47. addButton("1", 0, 4, 1, 1, insert);
  48. addButton("2", 1, 4, 1, 1, insert);
  49. addButton("3", 2, 4, 1, 1, insert);
  50. addButton("-", 3, 4, 1, 1, command);
  51. addButton("0", 0, 5, 1, 1, insert);
  52. // addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
  53. addButton(".", 2, 5, 1, 1, insert);
  54. addButton("+", 3, 5, 1, 1, command);
  55. addButton("=", 0, 6, 4, 1, command);
  56. this.setResizable(false);
  57. setSize(180, 200);
  58. setVisible(true);
  59. }
  60. private void addButton(String label, int row, int column, int with,
  61. int height, ActionListener listener) {
  62. JButton button = new JButton(label);
  63. constraints.gridx = row;
  64. constraints.gridy = column;
  65. constraints.gridwidth = with;
  66. constraints.gridheight = height;
  67. constraints.fill = GridBagConstraints.BOTH;
  68. button.addActionListener(listener);
  69. layout.setConstraints(button, constraints);
  70. container.add(button);
  71. }
  72. private class InsertAction implements ActionListener {
  73. public void actionPerformed(ActionEvent event) {
  74. String input = event.getActionCommand();
  75. if (start) {
  76. displayField.setText("");
  77. start = false;
  78. if (input.equals("+/-"))
  79. displayField.setText(displayField.getText() + "-");
  80. }
  81. if (!input.equals("+/-")) {
  82. if (input.equals("Backspace")) {
  83. String str = displayField.getText();
  84. if (str.length() > 0)
  85. displayField.setText(str.substring(0, str.length() - 1));
  86. } else if (input.equals("CE") || input.equals("C")) {
  87. displayField.setText("0");
  88. start = true;
  89. } else
  90. displayField.setText(displayField.getText() + input);
  91. }
  92. }
  93. }
  94. private class CommandAction implements ActionListener {
  95. public void actionPerformed(ActionEvent evt) {
  96. String command = evt.getActionCommand();
  97. if (start) {
  98. lastCommand = command;
  99. } else {
  100. calculate(Double.parseDouble(displayField.getText()));
  101. lastCommand = command;
  102. start = true;
  103. }
  104. }
  105. }
  106. public void calculate(double x) {
  107. if (lastCommand.equals("+"))
  108. result += x;
  109. else if (lastCommand.equals("-"))
  110. result -= x;
  111. else if (lastCommand.equals("*"))
  112. result *= x;
  113. else if (lastCommand.equals("/"))
  114. result /= x;
  115. else if (lastCommand.equals("="))
  116. result = x;
  117. displayField.setText("" + result);
  118. }
  119. public static void main(String[] args) {
  120. Calculator calculator = new Calculator();
  121. calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  122. }
  123. }
复制代码

方法二：

  2. import java.awt.*;
  3. import java.awt.event.*;
  4. public class MyCalculator {
  5. PRivate Frame f;
  6. private TextField tf = new TextField(30);
  7. private long result;
  8. private boolean append=false;
  9. private char Operator='=';
  10. private Button[] btn=new Button[15];
  11. public MyCalculator() {
  12. initComponent();
  13. }
  14. private void initComponent() {
  15. f = new Frame("My Calculator V1.0");
  16. f.setLayout(new BorderLayout()); //The frame uses BorderLayout
  17. f.addWindowListener(new WindowAdapter() {
  18. public void windowClosing(WindowEvent evt) {
  19. System.exit(0);
  20. }
  21. });
  22. Panel centerPanel = new Panel();
  23. centerPanel.setLayout(new GridLayout(5, 3)); //The panel uses GridLayout
  24. NumberListener nl=new NumberListener();
  25. OperatorListener ol=new OperatorListener();
  26. btn[10]=new Button("+");
  27. btn[11]=new Button("-");
  28. btn[12]=new Button("*");
  29. btn[13]=new Button("/");
  30. btn[14]=new Button("=");
  31. for (int i=0;i<=9;i++){
  32. btn[i]=new Button(String.valueOf(i));
  33. centerPanel.add(btn[i]);
  34. btn[i].addActionListener(nl);
  35. if (i%2==1){
  36. centerPanel.add(btn[(i+19)/2]);
  37. btn[(i+19)/2].addActionListener(ol);
  38. }
  39. }
  40. f.add(centerPanel, BorderLayout.CENTER);
  41. Panel northPanel = new Panel();
  42. tf.setEditable(false);
  43. northPanel.add(tf);
  44. f.add(northPanel, BorderLayout.NORTH);
  45. }
  46. public void go() {
  47. f.pack();
  48. f.setVisible(true);
  49. }
  50. public static void main(String[] args) {
  51. new MyCalculator().go();
  52. }
  53. /**
  54. *采用成员内部类方式，实现监听器接口，方便访问主类内类内部成员。
  55. *此类负责数字按钮Action事件监听和处理
  56. */
  57. class NumberListener implements ActionListener{
  58. public void actionPerformed(ActionEvent e){
  59. if (!append) {
  60. tf.setText("");
  61. append=true;
  62. }
  63. String s=tf.getText();
  64. s+=e.getActionCommand();
  65. tf.setText(s);
  66. if (!btn[10].isEnabled()){
  67. for(int i=10;i<=14;i++) btn[i].setEnabled(true);
  68. }
  69. }
  70. }
  71. /**
  72. * 成员内部类，负责操作符按钮的事件处理
  73. */
  74. class OperatorListener implements ActionListener{
  75. public void actionPerformed(ActionEvent e){
  76. if (!append) return;
  77. for(int i=10;i<=14;i++) btn[i].setEnabled(false);
  78. String s=tf.getText();
  79. long num=Long.parseLong(s);//get the number of textfield
  80. append=false; //set append
  81. switch(operator){
  82. case '+':result+=num;break;
  83. case '-':result-=num;break;
  84. case '*':result*=num;break;
  85. case '/':{
  86. if (num==0) result=0;
  87. else result/=num;
  88. break;
  89. }
  90. case '=':result=num;break;
  91. }
  92. tf.setText(String.valueOf(result));
  93. //set the value of result to textfield
  94. String op=e.getActionCommand();
  95. operator=op.charAt(0); // set operator
  96. }
  97. }
  98. }
复制代码

方法三：

  2. package wanwa;
  3. import java.util.*;
  4. public class calc {
  5. public static void main(String[] args) {
  6. Scanner input = new Scanner(System.in);
  7. System.out.println("*****************简易计算器****************");
  8. System.out.println("*ttttt*");
  9. System.out.println("* 使用说明： 1.加法 2.减法 3.乘法 4.除法 *");
  10. System.out.println("*ttttt*");
  11. System.out.println("*****************************************");
  12. for(int i=0;i<100;i++){
  13. System.out.print("n请选择运算规则：");
  14. int num = input.nextInt();
  15. switch(num){
  16. case 1:
  17. System.out.println("n******你选择了加法******n");
  18. System.out.print("请输入第1个加数:");
  19. int jiashu1 = input.nextInt();
  20. System.out.print("请输入第2个加数:");
  21. int jiashu2 = input.nextInt();
  22. System.out.println("运算结果为:" + jiashu1 + " + " + jiashu1 + " = " + (jiashu1 + jiashu2));
  23. break;
  24. case 2:
  25. System.out.println("n******你选择了减法******n");
  26. System.out.print("请输入被减数:");
  27. int jianshu1 = input.nextInt();
  28. System.out.print("请输入减数:");
  29. int jianshu2 = input.nextInt();
  30. System.out.println("运算结果为:" + jianshu1 + " - " + jianshu2 + " = " + (jianshu1 - jianshu2));
  31. break;
  32. case 3:
  33. System.out.println("n******你选择了乘法******n");
  34. System.out.print("请输入第1个因数:");
  35. int chengfa1 = input.nextInt();
  36. System.out.print("请输入第2个因数:");
  37. int chengfa2 = input.nextInt();
  38. System.out.println("运算结果为:" + chengfa1 + " * " + chengfa2 + " = " + (chengfa1 * chengfa2));
  39. break;
  40. case 4:
  41. System.out.println("n******你选择了除法******n");
  42. System.out.print("请输入被除数:");
  43. double chufa1 = input.nextInt();
  44. System.out.print("请输入除数:");
  45. double chufa2 = input.nextInt();
  46. System.out.println("运算结果为:" + chufa1 + " / " + chufa2 + " = " + (chufa1 / chufa2) + " 余 " + (chufa1 % chufa2));
  47. break;
  48. default:
  49. System.out.println("n你的选择有错，请重新选择!");
  50. break;
  51. }
  52. }
  53. }
  54. }
复制代码

方法四：

  2. package wanwa;
  3. import java.awt.*;
  4. import java.awt.event.*;
  5. import javax.swing.*;
  6. public class Calculator extends JFrame {
  7. private Container container;
  8. private GridBagLayout layout;
  9. private GridBagConstraints constraints;
  10. private JTextField displayField;// 计算结果显示区
  11. private String lastCommand;// 保存+,-,*,/,=命令
  12. private double result;// 保存计算结果
  13. private boolean start;// 判断是否为数字的开始
  14. public Calculator() {
  15. super("Calculator");
  16. container = getContentPane();
  17. layout = new GridBagLayout();
  18. container.setLayout(layout);
  19. constraints = new GridBagConstraints();
  20. start = true;
  21. result = 0;
  22. lastCommand = "=";
  23. displayField = new JTextField(20);
  24. displayField.setHorizontalAlignment(JTextField.RIGHT);
  25. constraints.gridx = 0;
  26. constraints.gridy = 0;
  27. constraints.gridwidth = 4;
  28. constraints.gridheight = 1;
  29. constraints.fill = GridBagConstraints.BOTH;
  30. constraints.weightx = 100;
  31. constraints.weighty = 100;
  32. layout.setConstraints(displayField, constraints);
  33. container.add(displayField);
  34. ActionListener insert = new InsertAction();
  35. ActionListener command = new CommandAction();
  36. // addButton("Backspace", 0, 1, 2, 1, insert);
  37. // addButton("CE", 2, 1, 1, 1, insert);
  38. // addButton("C", 3, 1, 1, 1, insert);
  39. addButton("7", 0, 2, 1, 1, insert);
  40. addButton("8", 1, 2, 1, 1, insert);
  41. addButton("9", 2, 2, 1, 1, insert);
  42. addButton("/", 3, 2, 1, 1, command);
  43. addButton("4", 0, 3, 1, 1, insert);
  44. addButton("5", 1, 3, 1, 1, insert);
  45. addButton("6", 2, 3, 1, 1, insert);
  46. addButton("*", 3, 3, 1, 1, command);
  47. addButton("1", 0, 4, 1, 1, insert);
  48. addButton("2", 1, 4, 1, 1, insert);
  49. addButton("3", 2, 4, 1, 1, insert);
  50. addButton("-", 3, 4, 1, 1, command);
  51. addButton("0", 0, 5, 1, 1, insert);
  52. // addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
  53. addButton(".", 2, 5, 1, 1, insert);
  54. addButton("+", 3, 5, 1, 1, command);
  55. addButton("=", 0, 6, 4, 1, command);
  56. this.setResizable(false);
  57. setSize(180, 200);
  58. setVisible(true);
  59. }
  60. private void addButton(String label, int row, int column, int with,
  61. int height, ActionListener listener) {
  62. JButton button = new JButton(label);
  63. constraints.gridx = row;
  64. constraints.gridy = column;
  65. constraints.gridwidth = with;
  66. constraints.gridheight = height;
  67. constraints.fill = GridBagConstraints.BOTH;
  68. button.addActionListener(listener);
  69. layout.setConstraints(button, constraints);
  70. container.add(button);
  71. }
  72. private class InsertAction implements ActionListener {
  73. public void actionPerformed(ActionEvent event) {
  74. String input = event.getActionCommand();
  75. if (start) {
  76. displayField.setText("");
  77. start = false;
  78. if (input.equals("+/-"))
  79. displayField.setText(displayField.getText() + "-");
  80. }
  81. if (!input.equals("+/-")) {
  82. if (input.equals("Backspace")) {
  83. String str = displayField.getText();
  84. if (str.length() > 0)
  85. displayField.setText(str.substring(0, str.length() - 1));
  86. } else if (input.equals("CE") || input.equals("C")) {
  87. displayField.setText("0");
  88. start = true;
  89. } else
  90. displayField.setText(displayField.getText() + input);
  91. }
  92. }
  93. }
  94. private class CommandAction implements ActionListener {
  95. public void actionPerformed(ActionEvent evt) {
  96. String command = evt.getActionCommand();
  97. if (start) {
  98. lastCommand = command;
  99. } else {
  100. calculate(Double.parseDouble(displayField.getText()));
  101. lastCommand = command;
  102. start = true;
  103. }
  104. }
  105. }
  106. public void calculate(double x) {
  107. if (lastCommand.equals("+"))
  108. result += x;
  109. else if (lastCommand.equals("-"))
  110. result -= x;
  111. else if (lastCommand.equals("*"))
  112. result *= x;
  113. else if (lastCommand.equals("/"))
  114. result /= x;
  115. else if (lastCommand.equals("="))
  116. result = x;
  117. displayField.setText("" + result);
  118. }
  119. public static void main(String[] args) {
  120. Calculator calculator = new Calculator();
  121. calculator.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
  122. }
  123. }
复制代码

希望本文所述对大家java程序设计有所帮助。

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