Java 简单计算器

向右看齐 2022-05-17 08:06 297阅读 0赞

直接上代码

package cal;
    
    public class Main {
        public static void main(String[] args) {
            Demo.createGrid();
        }
    }

**生成界面：**

package cal;
    
    import java.awt.BorderLayout;
    import java.awt.Font;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import javax.swing.JTextArea;
    import javax.swing.JTextField;
    
    public class Demo extends JFrame { 
    
    
        public static void createGrid() {
    
            Font fn = new Font("黑体", Font.BOLD, 25);
    
            JFrame jf = new JFrame("计算器");
    
    
            jf.setBounds(600, 100, 600, 700);
    
            jf.setLayout(new BorderLayout());// 将界面设置为边界布局
            // 创建一个装文本的容器
            JPanel text = new JPanel(new GridLayout(2, 1));
    
            // 创建一个文本框
            JTextField jt = new JTextField(40);
            jt.setHorizontalAlignment(JTextField.RIGHT);
            jt.setFont(fn);
            jt.setText("0");
    
    
            // 创建一个文本域
            JTextArea ja = new JTextArea(2, 40);
            ja.setFont(fn);
    
            text.add(jt);
            text.add(ja);
    
            // jt.requestFocus();
    
            // 给按钮建一个网格布局
            JPanel jp = new JPanel(new GridLayout(5, 5));
            String[] str = { "CE", "C", "DEL", "%", "/", "sin", "1", "2", "3", "*", "cos", "4", "5", "6", "-", "tan", "7",
                    "8", "9", "+", "(", ")", "0", ".", "=" };
    
            JButton[] bu = new JButton[str.length];
    
            for (int i = 0; i < 25; i++) {
                bu[i] = new JButton(str[i]);
                bu[i].setFont(fn);
                bu[i].setContentAreaFilled(false);//将按钮设为透明
    
                String str1 = bu[i].getText();
                if (str1.equals("tan") || str1.equals("cos") || str1.equals("sin")) {
                    bu[i].addActionListener(new ActionListener() {
                        @Override
                        public void actionPerformed(ActionEvent e) {
                            String s = jt.getText();
                            if (s.compareTo("0") == 0) {
                                jt.setText(str1 + "(");
                            } else {
                                jt.setText(new StringBuffer(s).append(str1).append("(").toString());
                            }
                        }
                    });
                } else if (str1.equals("DEL")) {
                    bu[i].addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            StringBuffer sb = new StringBuffer(jt.getText());
                            if (sb.length() == 1) {
                                jt.setText("0");
                            } else {
                                jt.setText(sb.deleteCharAt(sb.length() - 1).toString());
                            }
                            ja.setText("");
                        }
                    });
                } else if (str1.equals("CE")) {
                    bu[i].addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            StringBuffer sb = new StringBuffer(jt.getText());
                            for (int i = sb.length() - 1; i >= 0
                                    && (Character.isDigit(sb.charAt(i)) || sb.charAt(i) == '.'); i--) {
                                sb.deleteCharAt(i);
                            }
                            if (sb.length() == 0) {
                                sb.append('0');
                            }
                            jt.setText(sb.toString());
                            ja.setText("");
                        }
                    });
                } else if (str1.equals("C")) {
                    bu[i].addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            jt.setText("0");
                            ja.setText("");
                        }
                    });
                } else if (str1.equals("=")) {
                    bu[i].addActionListener(new ActionListener() {
    
                        @Override
                        public void actionPerformed(ActionEvent e) {
                            String s = jt.getText();
    
                            ja.setText(ReversePolish.reverse(s));
                            // jt.requestFocus();
                        }
    
                    });
                } else {
                    bu[i].addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            String s = jt.getText();
                            if (s.compareTo("0") == 0 && !judge(str1)) {
                                jt.setText(str1);
                            } else {
                                jt.setText(s + str1);
                            }
                        }
                    });
                }
    
                jp.add(bu[i]);
            }
    
            jf.add(text, BorderLayout.NORTH);
            jf.add(jp);
            jf.setVisible(true);
        }
    
        private static boolean judge(String s) {
            if (s.equals("+") || s.equals("-") || s.equals("*") || s.equals("/") || s.equals("%") || s.equals(".")) {
                return true;
            } else {
                return false;
            }
        }
    
    }

**运算处理：**

package cal;
    
    import java.util.LinkedList;
    
    public class ReversePolish {
    
        private static LinkedList<String> number = new LinkedList<String>();
        private static LinkedList<String> symbol = new LinkedList<String>();
        private static LinkedList<String> operation = new LinkedList<String>();
    
        private static void initialization(){
            number.clear();
            symbol.clear();
            operation.clear();
        }
    
        private static String[] handle(String s) {
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < s.length(); i++) {
                char ch = s.charAt(i);
                if (ch == '+'||ch == '-'||ch == '*'||ch == '/'||ch == '(' || ch == ')'||ch == '%') {
                    int index = sb.length();
                    if(index > 0 && sb.charAt(index-1) != ' ') {
                        sb.append(' ');
                    }
                    sb.append(ch).append(' ');
    
                } else if (ch == 't') {
                    sb.append("tan");
                    i += 2;
    
                } else if (ch == 's') {
                    sb.append("sin");
                    i += 2;
    
                } else if (ch == 'c') {
                    sb.append("cos");
                    i += 2;
    
                } else {
                    sb.append(ch);
                }
            }
    
    
            return sb.toString().trim().split(" ");
        }
    
        public static String reverse(String s) {
            initialization();
    
            String[] str = handle(s);
    
            //构建逆波兰表达式
            for (String ss : str) {
                //System.out.println(ss);
    
                if (Character.isDigit(ss.charAt(0))) {
                    number.add(ss);
                } else if (symbol.size() == 0) {
                    symbol.add(ss);
                } else if (judge(symbol.getFirst(), ss)) {
                    symbol.addFirst(ss);
                } else {
                    if (ss.compareTo(")") == 0) {
                        while (!symbol.isEmpty()) {
                            if (symbol.getFirst().compareTo("(") == 0) {
                                symbol.removeFirst();
                                if(symbol.isEmpty()) {
                                    break;
                                }
                                if((symbol.getFirst().equals("tan")||symbol.getFirst().equals("sin")||symbol.getFirst().equals("cos"))) {
    
                                    number.add(symbol.removeFirst());
                                }
                                break;
                            } else {
                                number.add(symbol.removeFirst());
                            }
                        }
                    } else {
                        while (!symbol.isEmpty() && !judge(symbol.getFirst(), ss)) {
                            number.add(symbol.removeFirst());
                        }
                        symbol.addFirst(ss);
                    }
                }
            }
            while (!symbol.isEmpty()) {
                number.add(symbol.removeFirst());
            }
    
            //计算结果
            for (int i = 0; i < number.size(); i++) {
                //System.out.println(number.get(i));
    
                char ch = number.get(i).charAt(0);
                if (Character.isDigit(ch)) {
                    operation.addFirst(number.get(i));
    
                } else if (ch == 't') {
                    double a = Math.toRadians(Double.valueOf(operation.removeFirst()));
                    operation.addFirst(String.valueOf(Math.tan(a)));
    
                } else if (ch == 's') {
                    double a = Math.toRadians(Double.valueOf(operation.removeFirst()));
                    operation.addFirst(String.valueOf(Math.sin(a)));
    
                } else if (ch == 'c') {
                    double a = Math.toRadians(Double.valueOf(operation.removeFirst()));
                    operation.addFirst(String.valueOf(Math.cos(a)));
    
                } else if (ch == '*') {
                    double a = Double.valueOf(operation.removeFirst());
                    double b = Double.valueOf(operation.removeFirst());
                    operation.addFirst(delSuffixZero(new StringBuffer(String.valueOf(b * a))));
    
                } else if (ch == '/') {
                    if(number.get(i-1).compareTo("0") == 0){
                        return "除数不能为零！";
                    }
                    double a = Double.valueOf(operation.removeFirst());
                    double b = Double.valueOf(operation.removeFirst());
                    System.out.println(a+" "+b+" "+String.valueOf(b/a));
                    operation.addFirst(delSuffixZero(new StringBuffer(String.valueOf(b / a))));
    
                } else if (ch == '%') {
                    String a = operation.removeFirst();
                    String b = operation.removeFirst();
                    if(a.indexOf('.') != -1 || b.indexOf('.') != -1) {
                        return "浮点类型数据不能进行取模运算！";
                    }
                    operation.addFirst(String.valueOf(Integer.valueOf(b) % Integer.valueOf(a)));
    
                } else if (ch == '+') {
                    double a = Double.valueOf(operation.removeFirst());
                    double b = Double.valueOf(operation.removeFirst());
                    operation.addFirst(delSuffixZero(new StringBuffer(String.valueOf(b + a))));
    
                } else if (ch == '-') {
                    double a = Double.valueOf(operation.removeFirst());
                    double b = Double.valueOf(operation.removeFirst());
                    operation.addFirst(delSuffixZero(new StringBuffer(String.valueOf(b - a))));
    
                }
            }
    
            return operation.getFirst();
        }
    
        private static String delSuffixZero(StringBuffer str) {
            int start = str.indexOf(".");
            int end = str.length();
            int i;
            for(i = end-1; i >= start && str.charAt(i) == '0'; i--);
            if(i < end-1) {
                str.delete(i, end);
            }
            return str.toString();
        }
    
        /* * 判断栈顶符号与待进栈符号的优先级 s为栈顶符号，s2为待进栈符号 若s2优先级小于 * 等于s返回false，否则返回true */
        private static boolean judge(String s, String s2) {
            if (s2.compareTo(")") == 0) {
                return false;
            } else if (s2.compareTo("-") == 0 || s2.compareTo("+") == 0) {
                if(s.equals("(") || s.equals("tan") || s.equals("sin") || s.equals("cos")) {
                    return true;
                }
                return false;
            } else if (s2.compareTo("*") == 0 || s2.compareTo("/") == 0 || s2.compareTo("%") == 0) {
                if (s.compareTo("*") == 0 || s2.compareTo("/") == 0 || s2.compareTo("%") == 0) {
                    return false;
                } else {
                    return true;
                }
            } else {
                return true;
            }
        }
    
    }

**效果图：**  
![这里写图片描述][70]

[70]: /images/20220517/f259e819724e462d8e4963c341412d8b.png