package jisuanqi;
import java.awt.BorderLayout;
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;

public class jisuanqi extends JFrame implements ActionListener
{
	JFrame jf=new JFrame("计算器");
	GridLayout g=new GridLayout(5,4);
	JTextField jtf=new JTextField("0",20);
	boolean com=false; 
	int i=0; 
	String sum=""; 
	double total=0; 
	int xuhao=0;
	jisuanqi()
	{
		jf.add(jtf,BorderLayout.NORTH);
		JPanel jp=new JPanel();
		jp.setLayout(g);
		jf.add(jp);
		String[] lab = {"BackS","CE","C","+","7","8","9","-","4","5","6","*","1","2","3","/","0",".","+/-","="};
		for(int i=0;i<lab.length;i++)
		{
			JButton jb = new JButton(lab[i]);
			jp.add(jb);
			jb.addActionListener(this);
		}
		jf.setLocation(300, 300);
		jf.setSize(200,300);
		jf.setVisible(true);
		jf.pack();
		jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	
	}
	public void actionPerformed(ActionEvent e)
	{
		String comm=e.getActionCommand();
		if("0123456789".indexOf(comm)!=-1)
		{
			if (com || i == 0)                                        
			{ 
				jtf.setText(comm); 
				com = false; 
				i = 1; 
			} 
			else
			{ 
				sum = jtf.getText(); 
				if("0".equals(comm)&&!(Double.parseDouble(sum) > 0 || Double.parseDouble(sum) < 0))
				{
					if (sum.trim().indexOf(".") == -1)
					{ 
						jtf.setText(sum); 
					} 
					else 
					{ 
						jtf.setText(sum + "0"); 
					} 
				}
				jtf.setText(sum + comm); 
			} 
		}
		else if ("CE".equals(comm)||"C".equals(comm)) 
		{ 
			jtf.setText(""); 
			i = 0; 
			com = true; 
		}  
		else if (e.getActionCommand().equals(".")) 
		{ 
			if (com || i == 0)
			{ 
				jtf.setText("0."); 
				com = false; 
				i = 1; 
			} 
			else 
			{ 
				sum = jtf.getText(); 
				if (sum.trim().indexOf(".") == -1)
				{
					jtf.setText(sum + "."); 
				} 
				else 
				{ 
					jtf.setText(sum); 
				} 
			} 
		}
		else if("+-*/".indexOf(comm)!=-1)
		{
			com = true; 
			i = 0; 
			total = Double.parseDouble(jtf.getText());
			if("+".equals(comm))
				xuhao = 1; 
			else if("-".equals(comm))
				xuhao=2;
			else if("*".equals(comm))
				xuhao = 3; 
			else if("/".equals(comm))
				xuhao=4;
		}
		else if("BackS".equals(comm))
		{
			String s=jtf.getText();
			if(s.length()>0)
			{
				jtf.setText(s.substring(0,s.length()-1));
			}
		}
		else if("+/-".equals(comm))
		{
			String s=jtf.getText();
			if(s.startsWith("-"))
			{
				jtf.setText(s.substring(1));
			}
			else
			{
				jtf.setText("-"+s);
			}
		}
		else if ("=".equals(comm)) 
		{ 
			switch (xuhao) 
			{ 
			case 1 : 
			{ 
				double ad = total + Double.parseDouble(jtf.getText()); 
				jtf.setText(ad + ""); 
				i = 0; 
				sum = ""; 
				break; 
			} 
			case 2 : 
			{ 
				double ad = total - Double.parseDouble(jtf.getText()); 
				jtf.setText(String.valueOf(ad)); 
				i = 0; 
				sum = ""; 
				break; 
			} 
			case 3 : 
			{ 
				double ad = total * Double.parseDouble(jtf.getText()); 
				jtf.setText(ad + ""); 
				i = 0; 
				sum = ""; 
				break; 
			} 
			case 4 : 
			{ 
				double ad = total / Double.parseDouble(jtf.getText()); 
				jtf.setText(ad + ""); 
				i = 0; 
				sum = ""; 
				break; 
			} 
		} 
		System.out.println(com); 
		repaint();
		} 
	}
	public static void main(String[] args) 
	{
		new jisuanqi();
	}
}