简单计算器

简单计算器

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Calculator extends JFrame
{
	JTextField windows;
	JButton data0,data1,data2,data3,data4,data5,data6,data7,data8;
	JButton data9,datajia,datajian,datacheng,datachu,dataequl,databack;
	JButton clear;
	JPanel pbutton;
	InnerPolice police;
	String data=" ";
    double[] number=new double[10];
	char[] signal=new char[10];
	public Calculator()
	{
		windows=new JTextField(34);                       //设置显示窗口
		//windows.setSize(20, 20);
		windows.setEditable(false);
		JPanel Pwindows=new JPanel();
		Pwindows.add(windows);
		
		data0=new JButton("0");                                  //定义按键以及字体
		data0.setFont(new Font("宋体",Font.BOLD,30));
		data1=new JButton("1");
		data1.setFont(new Font("宋体",Font.BOLD,30));
		data2=new JButton("2");
		data2.setFont(new Font("宋体",Font.BOLD,30));
		data3=new JButton("3");
		data3.setFont(new Font("宋体",Font.BOLD,30));
		data4=new JButton("4");
		data4.setFont(new Font("宋体",Font.BOLD,30));
		data5=new JButton("5");
		data5.setFont(new Font("宋体",Font.BOLD,30));
		data6=new JButton("6");
		data6.setFont(new Font("宋体",Font.BOLD,30));
		data7=new JButton("7");
		data7.setFont(new Font("宋体",Font.BOLD,30));
		data8=new JButton("8");
		data8.setFont(new Font("宋体",Font.BOLD,30));
		data9=new JButton("9");
		data9.setFont(new Font("宋体",Font.BOLD,30));
		datajia=new JButton("+");
		datajia.setFont(new Font("宋体",Font.BOLD,30));
		datajian=new JButton("-");
		datajian.setFont(new Font("宋体",Font.BOLD,30));
		datacheng=new JButton("*");
		datacheng.setFont(new Font("宋体",Font.BOLD,30));
		datachu=new JButton("/");
		datachu.setFont(new Font("宋体",Font.BOLD,30));
		dataequl=new JButton("=");
		dataequl.setFont(new Font("宋体",Font.BOLD,30));
		databack=new JButton("backspace");
		databack.setFont(new Font("宋体",Font.BOLD,30));
		
		clear=new JButton("删除");
		clear.setFont(new Font("宋体",Font.BOLD,30));
		//clear.setSize(100, 10);
		//clear.addActionListener(police);
		JPanel pclear=new JPanel();
		pclear.add(clear);
		
		pbutton=new JPanel();                                      //向容器中添加按钮
		pbutton.setLayout(new GridLayout(4,4));
		pbutton.add(data1);
		pbutton.add(data2);
		pbutton.add(data3);
		pbutton.add(datajia);
		pbutton.add(data4);
		pbutton.add(data5);
		pbutton.add(data6);
		pbutton.add(datajian);
		pbutton.add(data7);
		pbutton.add(data8);
		pbutton.add(data9);
		pbutton.add(datacheng);
		pbutton.add(data0);
		pbutton.add(databack);
		pbutton.add(dataequl);
		pbutton.add(datachu);
		setBounds(100,100,400,260);
		setVisible(true);
	    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	    
	    add(Pwindows,BorderLayout.NORTH);
	    add(pbutton,BorderLayout.CENTER);
	    add(pclear,BorderLayout.SOUTH);
	   
	    police=new InnerPolice();                               //添加监视器进行监视
	    data0.addActionListener(police);
	    data1.addActionListener(police);
	    data2.addActionListener(police);
	    data3.addActionListener(police);
	    data4.addActionListener(police);
	    data5.addActionListener(police);
	    data6.addActionListener(police);
	    data7.addActionListener(police);
	    data8.addActionListener(police);
	    data9.addActionListener(police);
	    datajia.addActionListener(police);
	    datajian.addActionListener(police);
	    datacheng.addActionListener(police);
	    datachu.addActionListener(police);
	    dataequl.addActionListener(police);
	    databack.addActionListener(police);
	    clear.addActionListener(police);
	}
	class InnerPolice implements ActionListener                           //监视器函数体
	{
		public void actionPerformed(ActionEvent e)
		{
			if(e.getSource()==clear)
			{
				//System.out.println("hello world");
				data=" ";
				windows.setText(data);
			}
			if(e.getSource()==data0)
			  {
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			  }
			if(e.getSource()==data1)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data2)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data3)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data4)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data5)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data6)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data7)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data8)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==data9)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==datajia)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==datajian)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==datacheng)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==datachu)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
			if(e.getSource()==databack)
			{
				int lengthofdata=data.length();                        
				if(lengthofdata==1)
					;
				else
				   lengthofdata--;
				data=data.substring(0,lengthofdata);
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
				//System.out.println(data);
			}
			if(e.getSource()==dataequl)
			{
				data+=e.getActionCommand();
				windows.setText(data);
				int n=data.length();
				String memorial; 
				int fore=1,end,lengthofnumber=0,lengthofsignal=0;
				double now;
				for(int i=0;i<n;i++)    //以运算符号作为标志，将数字以及运算符号分别入栈，并进行相应的处理
				    if(data.charAt(i)=='+'||data.charAt(i)=='-'||data.charAt(i)=='*'||data.charAt(i)=='/'||data.charAt(i)=='=')
					{
				    	end=i;
					    memorial=data.substring(fore, end);                          //将数字抽离出来
					   // System.out.println(fore+" "+end+" number:"+memorial+" signal:"+data.charAt(i));
					    number[lengthofnumber++]=Integer.parseInt(memorial);         //将数字入栈
					   
					    if(lengthofsignal==0)                                   //第一次时，
					    {
					    	signal[lengthofsignal++]=data.charAt(i);
						    //lengthofsignal++;
					    	fore=i+1;
					        continue;
					   	}
					    
					    if(signal[lengthofsignal-1]=='*')                //如果是乘法，则提前运算        
					    {
					    	now=number[--lengthofnumber];                //乘数出栈
					        double before=number[--lengthofnumber];      //被乘数出栈
					        now=before*now;
					        number[lengthofnumber++]=now;                //运算结果进栈
					        lengthofsignal--;                            //符号栈减一
					    }
					    else if(signal[lengthofsignal-1]=='/')           //如果是除法，则提前运算
					    {
					    	now=number[--lengthofnumber];                //除数出栈
					    	double before=number[--lengthofnumber];      //被除数出栈
					    	now=before/now;
					    	number[lengthofnumber++]=now;                //运算结果进栈
					    	lengthofsignal--;                            //符号栈减一
					    }
					    
					    //System.out.println(number[lengthofnumber]);
					    signal[lengthofsignal]=data.charAt(i);
					    lengthofsignal++;
					    fore=i+1;
					}	
				
				lengthofsignal--;
				//System.out.println("lengthofnumber:"+lengthofnumber+"  lengthofsignal:"+lengthofsignal);
				//for(int i=0;i<lengthofnumber;i++)
					//System.out.println("number["+i+"]"+number[i]);
				//for(int i=0;i<lengthofsignal;i++)
					//System.out.println("signal["+i+"]"+signal[i]);

				//int k=0;
				while(lengthofsignal!=0)                                       //计算剩余加减法
				{
                    //System.out.println("hello world"+lengthofsignal);
					if(signal[lengthofsignal-1]=='-')                          //判断是否是减法
					{
						//System.out.println("test:"+lengthofsignal);
						now=number[--lengthofnumber];                          //减数出栈
						double before=number[--lengthofnumber];                //被减数判断
						now=before-now;
						number[lengthofnumber++]=now;                          //将结果入栈
						lengthofsignal--;                                      //符号出栈
						//System.out.println("values:"+now);
					}
					else if(signal[lengthofsignal-1]=='+')                     //判断是否是加法
					{
						//System.out.println("test:"+lengthofsignal);
						now=number[--lengthofnumber];                          //加数出栈
						double before=number[--lengthofnumber];                //被加数出栈
						now=before+now;
						number[lengthofnumber++]=now;                          //将结果入栈 
						lengthofsignal--;                                      //符号出栈
						//System.out.println("values:"+now);
					}
				}
				String values=""+number[0];
				//System.out.println(values);
				data+=values;
				windows.setText(data);
				windows.setFont(new Font("宋体",Font.BOLD,20));
			}
		}
		
	}
	
	public static void main(String[] args)
	{
		new Calculator();
	}
}

结果：