24点扑克牌游戏——（含java源码）（GUI实现）

给出四个数字，要求，在其间添加运算符和括号，使得计算结果等于24。

括号的放置即为决定哪几个数先进行计算。所以，我们先确定首先进行计算的两个相邻的数，计算完成后，就相当于剩下三个数字，仍需要在它们之间添加符号；然后再决定在这三个数中哪两个相邻的数先计算。由此，我们就成功解决了数字的运算次序问题，此时不需要再考虑不同运算符号的优先级问题，因为括号的优先级高于加减乘除。

通过循环，我们可以得到第一第二第三次计算的运算符，再通过计算，就可以得出和，若和等于24，即为所求解。

在输出格式中，由于括号的放置共六种情况，故根据计算先后顺序的不同，输出时在不同地方放置括号；

以下是java源码：

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.JOptionPane;

public class  TwentyFourPoke_Game extends JFrame
{
	private JButton jbsolution = new JButton("Find a Solution");
	private JButton jbrefresh = new JButton("Refresh");
	private JButton jbverify = new JButton("Verify");

	private JLabel jlmessage = new JLabel("Enter an expression:");

	private JTextField jtsolution = new JTextField();
	private JTextField jtexpression = new JTextField();

	private ImagePanel pp = new ImagePanel();

	private int[] card = new int[4];
	private double[] bcard = new double[4];

	private double sum;
	private double[] temp1 = new double[3];
	private double[] temp2 = new double[2];
	private char[] sign = {'+','-','*','/'};

	public TwentyFourPoke_Game()
	{
		JPanel p1 = new JPanel(new GridLayout(1,3));
		p1.add(jbsolution);
		p1.add(jtsolution);
		p1.add(jbrefresh);
		JPanel p3 = new JPanel(new GridLayout(1,3));
		p3.add(jlmessage);
		p3.add(jtexpression);
		p3.add(jbverify);

		add(p1,BorderLayout.NORTH);
		add(pp,BorderLayout.CENTER);
		add(p3,BorderLayout.SOUTH);

		ButtonListener listener = new ButtonListener();
		jbsolution.addActionListener(listener);
		jbrefresh.addActionListener(listener);
		jbverify.addActionListener(listener);
	}

	class ButtonListener implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			if(e.getSource() == jbsolution)
			{
				for(int i = 0;i < 4;i++)
				{
					bcard[i] = (double)card[i] % 13;
					if(card[i] % 13 == 0)
						bcard[i] = 13;
				}
				search();
			}
			else if(e.getSource() == jbrefresh)
			{
				pp.sshow();

			}
			else if(e.getSource() == jbverify)
			{
				String expression = jtexpression.getText();
				int result = evaluateExpression(expression);
				if(result == 24)
				{
					JOptionPane.showMessageDialog(null,"恭喜你！你答对了！","消息框",JOptionPane.INFORMATION_MESSAGE);
				}
				else
				{
					JOptionPane.showMessageDialog(null,"抱歉！请再次尝试。","消息框",JOptionPane.INFORMATION_MESSAGE);
				}
			}
		}
	}

	public static double calcute(double a,double b,char c)
	{
		if(c == '+')
			return a+b;
		else if(c == '-')
			return  a-b;
		else if(c == '*')
			return a*b;
		else if(c == '/' && b != 0)
			return a/b;
		else
			return -1;
	}

	public  void search()
	{
		boolean judge = false;
		for(int i=0;i<4;i++)
		//第一次放置的符号
		{
			for(int j=0;j<4;j++)
			//第二次放置的符号
			{
				for(int k=0;k<4;k++)
				//第三次放置的符号
				{
					for(int m=0;m<3;m++)
					//首先计算的两个相邻数字，共有3种情况，相当于括号的作用
					{
						if(bcard[m+1]==0 && sign[i]=='/') break;
						temp1[m]=calcute(bcard[m],bcard[m+1],sign[i]);
						temp1[(m+1)%3]=bcard[(m+2)%4];
						temp1[(m+2)%3]=bcard[(m+3)%4];
						//先确定首先计算的两个数字，计算完成相当于剩下三个数，按顺序储存在temp数组中
						for(int n=0;n<2;n++)
						//三个数字选出先计算的两个相邻数字，两种情况，相当于第二个括号
						{
							if(temp1[n+1]==0 && sign[j]=='/') break;
							temp2[n]=calcute(temp1[n],temp1[n+1],sign[j]);
							temp2[(n+1)%2]=temp1[(n+2)%3];
							//先确定首先计算的两个数字，计算完成相当于剩下两个数，按顺序储存在temp数组中
							if(temp2[1]==0 && sign[k]=='/') break;
							sum=calcute(temp2[0],temp2[1],sign[k]);
							//计算和
							if(sum==24)
							//若和为24
							{
								judge=true;
								//判断符为1，表示已求得解
									if(m==0 && n==0)
									{
										String sss ="(("+(int)bcard[0]+sign[i]+(int)bcard[1]+")"+sign[j]+(int)bcard[2]+")"+sign[k]+(int)bcard[3]+"="+(int)sum;
										jtsolution.setText(sss);
										return ;
									}
									else if(m==0 && n==1)
									{
										String sss ="("+(int)bcard[0]+sign[i]+(int)bcard[1]+")"+sign[k]+"("+(int)bcard[2]+sign[j]+(int)bcard[3]+")="+(int)sum;
										jtsolution.setText(sss);
										return ;
									}
									else if(m==1 && n==0)
									{
										String sss ="("+(int)bcard[0]+sign[j]+"("+(int)bcard[1]+sign[i]+(int)bcard[2]+"))"+sign[k]+(int)bcard[3]+"="+(int)sum;
										jtsolution.setText(sss);
										return ;
									}
									else if(m==2 && n==0)
									{
										String sss ="("+(int)bcard[0]+sign[j]+(int)bcard[1]+")"+sign[k]+"("+(int)bcard[2]+sign[i]+(int)bcard[3]+")="+(int)sum;
										jtsolution.setText(sss);
										return ;
									}
									else if(m==2 && n==0)
									{
										String sss =(int)bcard[0]+sign[k]+"("+(int)bcard[1]+sign[j]+"("+(int)bcard[2]+sign[i]+(int)bcard[3]+"))="+(int)sum;
										jtsolution.setText(sss);
										return ;
									}
										//m=0,1,2 n=0,1表示六种括号放置可能，并按照这六种可能输出相应的格式的计算式

							}
						}
					}
				}
			}
		}
		if(judge==false)
			jtsolution.setText("No solution!");
		//如果没有找到结果，符号位为0
	}

	public static int evaluateExpression(String expression)
	{
		// Create operandStack to store operands
		java.util.Stack<Integer> operandStack = new java.util.Stack<Integer>();

		// Create operatorStack to store operators
		java.util.Stack<Character> operatorStack = new java.util.Stack<Character>();

		// Extract operands and operators
		java.util.StringTokenizer tokens = new java.util.StringTokenizer(expression, "()+-/*", true);

		// Phase 1: Scan tokens
		while (tokens.hasMoreTokens())
		{
			String token = tokens.nextToken().trim(); // Extract a token
			if (token.length() == 0) // Blank space
				continue; // Back to the while loop to extract the next token
			else if (token.charAt(0) == '+' || token.charAt(0) == '-')
			{
				// Process all +, -, *, / in the top of the operator stack
				while (!operatorStack.isEmpty() &&(operatorStack.peek().equals('+') ||operatorStack.peek().equals('-') || operatorStack.peek().equals('*') ||
           operatorStack.peek().equals('/')))
				{
					processAnOperator(operandStack, operatorStack);
				}
				// Push the + or - operator into the operator stack
				operatorStack.push(new Character(token.charAt(0)));
			}
			else if (token.charAt(0) == '*' || token.charAt(0) == '/')
			{
				// Process all *, / in the top of the operator stack
				while (!operatorStack.isEmpty() && (operatorStack.peek().equals('*') || operatorStack.peek().equals('/')))
				{
					processAnOperator(operandStack, operatorStack);
				}

				// Push the * or / operator into the operator stack
				operatorStack.push(new Character(token.charAt(0)));
			}
			else if (token.trim().charAt(0) == '(')
			{
				operatorStack.push(new Character('(')); // Push '(' to stack
			}
			else if (token.trim().charAt(0) == ')')
			{
				// Process all the operators in the stack until seeing '('
				while (!operatorStack.peek().equals('('))
				{
					 processAnOperator(operandStack, operatorStack);
				}
				operatorStack.pop(); // Pop the '(' symbol from the stack
			}
			else
			{
				// An operand scanned
				// Push an operand to the stack
				operandStack.push(new Integer(token));
			}
		}

		// Phase 2: process all the remaining operators in the stack
		while (!operatorStack.isEmpty())
		{
			processAnOperator(operandStack, operatorStack);
		}

		// Return the result
		return ((Integer)(operandStack.pop())).intValue();
	}

	public static void processAnOperator(java.util.Stack<Integer> operandStack,java.util.Stack<Character> operatorStack)
	{
		if (operatorStack.peek().equals('+'))
		{
			operatorStack.pop();
			int op1 = ((Integer)(operandStack.pop())).intValue();
			int op2 = ((Integer)(operandStack.pop())).intValue();
			operandStack.push(new Integer(op2 + op1));
		}
		else if (operatorStack.peek().equals('-'))
		{
			operatorStack.pop();
			int op1 = ((Integer)(operandStack.pop())).intValue();
			int op2 = ((Integer)(operandStack.pop())).intValue();
			operandStack.push(new Integer(op2 - op1));
		}
		else if (operatorStack.peek().equals('*'))
		{
			operatorStack.pop();
			int op1 = ((Integer)(operandStack.pop())).intValue();
			int op2 = ((Integer)(operandStack.pop())).intValue();
			operandStack.push(new Integer(op2 * op1));
		}
		else if (operatorStack.peek().equals('/'))
		{
			operatorStack.pop();
			int op1 = ((Integer)(operandStack.pop())).intValue();
			int op2 = ((Integer)(operandStack.pop())).intValue();
			operandStack.push(new Integer(op2 / op1));
		}
	}

	class ImagePanel extends JPanel
	{
		public void sshow()
		{
			int i;
			for(i = 0;i < 4;i++)
			{
				card[i] = (int)(1 + Math.random() * 52);
			}
			repaint();
		}

		protected void paintComponent(Graphics g)
		{
			super.paintComponent(g);
			int i;
			int w = getWidth() / 4;
			int h = getHeight();
			int x = 0;
			int y = 0;
			for(i = 0;i < 4;i++)
			{
				ImageIcon imageIcon = new ImageIcon("image/card/" + card[i] + ".png");
				Image image = imageIcon.getImage();
				if(image != null)
				{
					g.drawImage(image,x,y,w,h,this);
				}
				x += w;
			}
		}
	}

	public static void main(String[] args)
	{
		TwentyFourPoke_Game frame = new TwentyFourPoke_Game();
		frame.setTitle("24 Poke Game");
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(368,200);
		frame.setVisible(true);
	}
}