Java四则混合运算图形化计算器

秒速五厘米 2022-05-27 11:59 180阅读 0赞

最近在学习数据结构,学到Stack栈,想到用栈求表达式的值.为了看起来更好看一点,就写了一个GUI界面.![20180418130032312][]

package MyCalculator;
    
    import java.awt.BorderLayout;
    import java.awt.Container;
    import java.awt.Dimension;
    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.JTextField;
    import javax.swing.border.Border;
    
    public class MyCalc {
    	public static void main(String[] args) {
    		new myFrame("TWY计算器");
    	}
    
    }
    
    class myFrame extends JFrame  {
    
    	JTextField text = new JTextField();
    	
    	JButton[] bt = new JButton[20];
    	String key[] = new String[] { "ans", "del", "EC", "C", "1", "2", "3", "+", "4", "5", "6", "-", "7", "8", "9", "*",
    			"0", ".", "=", "/" };
    	JPanel keyPanel = new JPanel();
    
    	boolean finish = false;
    	double ans=0;
    
    	public myFrame(String title) {
    		super(title);
    		init();
    	}
    
    	public void init() {
    		text.setHorizontalAlignment(JTextField.RIGHT);
    		text.setPreferredSize(new Dimension(0, 40));
    		text.setFont(new Font("宋体", Font.BOLD, 20));
    		
    		for (int i = 0; i < bt.length; i++) {
    			bt[i] = new JButton(key[i]);
    		}
    		Container pane = this.getContentPane();
    		this.add(text, BorderLayout.NORTH);
    		keyPanel.setLayout(new GridLayout(5, 4, 3, 3));
    		this.add(keyPanel, BorderLayout.CENTER);
    		for (int i = 0; i < bt.length; i++) {
    			keyPanel.add(bt[i]);
    			bt[i].addActionListener(new ActionListener() {
    
    				public void actionPerformed(ActionEvent e) {
    
    					if (finish == true) {
    						text.setText("");
    						finish = false;
    					}
    					String command = e.getActionCommand();
    					String s = text.getText();
    					if ("0123456789.+-*/".indexOf(command) >= 0)
    						text.setText(text.getText() + command);
    					else if (command.equals("del"))
    						text.setText(s.substring(0, s.length() - 1));
    					else if (command.equals("C") || command.equals("EC"))
    						text.setText("");
    					else if (command.equals("ans") )
    						text.setText(text.getText() + ans);
    					else if (command.equals("=")) {
    						ans=new calc(s).result;
    						text.setText(text.getText() + "="+ans);
    						finish = true;
    					}
    
    				}
    			});
    		}
    		this.setVisible(true);
    		this.setLocation(500, 200);
    		this.setSize(325, 325);
    		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
    	}
    
    }

package MyCalculator;
    
    import java.util.Stack;
    
    class calc {
    	Stack<String> ops = new Stack<String>();
    	Stack<Double> num = new Stack<Double>();
    	String exp;
    	double result;
    
    	public calc(String s) {
    		exp = s;
    		calctor();
    	}
    
    	public void calctor() {
    		String s[] = tranform(exp).split(" ");
    		for (String string : s) {
    			if (string.matches("\\d+") || string.matches("\\d+.\\d+")) {
    				double n = Double.parseDouble(string);
    				num.push(n);
    			} else if (string.equals("+") || string.equals("-") || string.equals("/") || string.equals("*")) {
    				double op1 = num.pop(), op2 = num.pop();
    				switch (string) {
    				case "+":
    					num.push(op1 + op2);
    					break;
    				case "-":
    					num.push(op2 - op1);
    					break;
    				case "*":
    					num.push(op2 * op1);
    					break;
    				case "/":
    					num.push(op2 / op1);
    					break;
    				default:
    					break;
    				}
    
    			} else {
    
    			}
    		}
    		result = num.peek();
    //		System.out.println("ans= " + result);
    
    	}
    
    	public String tranform(String s) {
    		s = s.replace("+", " + ");
    		s = s.replace("-", " - ");
    		s = s.replace("*", " * ");
    		s = s.replace("/", " / ");
    		String str[] = s.split(" ");
    		String s1 = "";
    		for (String string : str) {
    			if (string.matches("\\d+") || string.matches("\\d+.\\d+")) {
    				s1 = s1 + " " + string;
    			} else {
    				if (ops.isEmpty()) {
    					ops.push(string);
    					continue;// 跳过下面
    				}
    				String temp = ops.peek();
    				while (priority(temp) >= priority(string)) {// 栈顶元素优先级高于或等于进栈元素,不断弹出栈顶元素
    					s1 = s1 + " " + temp;
    					ops.pop();
    					if (ops.isEmpty())
    						break;
    					temp = ops.peek();
    				}
    				ops.push(string);
    
    			}
    		}
    		while (!ops.isEmpty())
    			s1 = s1 + " " + ops.pop();
    //		System.out.println(s1);
    		return s1;
    
    	}
    
    	public int priority(String s) {
    		switch (s) {
    		case "+":
    		case "-":
    			return 1;
    		case "*":
    		case "/":
    			return 2;
    
    		default:
    			break;
    		}
    		return 0;
    
    	}
    }

[20180418130032312]: /images/20220527/8e51b7be39e3400bb761a313dee3b319.png