calculate.java

一个计算器的程序

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class calculate extends Applet implements ActionListener

{
	    double a=0.0,b=0.0;
	    String s="",ss="";
	    char sign='a';
	    Panel input11=new Panel();
	    Container p=new Container();
        Button btn1=new Button("1");
        Button btn2=new Button("2");
        Button btn3=new Button("3");
        Button btn4=new Button("+");
        Button btn5=new Button("4");
        Button btn6=new Button("5");
        Button btn7=new Button("6");
        Button btn8=new Button("-");
        Button btn9=new Button("7");
        Button btn10=new Button("8");
        Button btn11=new Button("9");
        Button btn12=new Button("*");
        Button btn13=new Button("cls");
        Button btn14=new Button("=");
        Button btn15=new Button("0");
        Button btn16=new Button("/");
        Button btn17=new Button(".");
        TextField input1=new TextField(68);
        Label input2=new Label("");
        Label input3=new Label("");
        Label input4=new Label("");      //初始化

		public void init()
		{
			setLayout(new BorderLayout());
			input1.setEditable(false);
			p.setLayout(new GridLayout(4,4));
			input11.add(input1);
			add("North",input11);
			//add(input4);
			//add(input1);
			//add(input2);
			//add(input3);
			p.add(btn1);
			p.add(btn2);
			p.add(btn3);
			p.add(btn4);
			p.add(btn5);
			p.add(btn6);
			p.add(btn7);
			p.add(btn8);
			p.add(btn9);
			p.add(btn10);
			p.add(btn11);
			p.add(btn12);
			p.add(btn13);
			p.add(btn14);
			p.add(btn15);
			p.add(btn16);
			add("Center",p);
			add("South",btn17);
			btn1.addActionListener(this);
			btn2.addActionListener(this);
			btn3.addActionListener(this);
			btn4.addActionListener(this);
			btn5.addActionListener(this);
			btn6.addActionListener(this);
			btn7.addActionListener(this);
			btn8.addActionListener(this);
			btn9.addActionListener(this);
			btn10.addActionListener(this);
			btn11.addActionListener(this);
			btn12.addActionListener(this);
			btn13.addActionListener(this);
			btn14.addActionListener(this);
			btn15.addActionListener(this);
			btn16.addActionListener(this);
		    btn17.addActionListener(this);
//监听
		}

		public void paint(Graphics g)
		{
		}

		public void actionPerformed(ActionEvent e)
		{
			if(e.getSource()==btn1)
			{
				s=s+"1";
				input1.setText(s);
		    }
		    if(e.getSource()==btn17)
						{
							s=s+"1";
							input1.setText(s);
		    }

		    else if(e.getSource()==btn2)
			{
				s=s+"2";
				input1.setText(s);
		    }

		    else if(e.getSource()==btn3)
			{
				s=s+"3";
				input1.setText(s);

		    }
		    else if(e.getSource()==btn4) //+
   			{
				b=a;
				a=Double.valueOf(s).doubleValue();
				switch(sign)
				{
					case '+': a=b+a; break;
					case '-': a=b-a; break;
					case '*': a=b*a; break;
					case '/': a=b/a; break;
				}
                s="";
                s=s+a;
				input1.setText(s);
				sign='+';
				s="";

		    }
		    else if(e.getSource()==btn5)
			{
				s=s+"4";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn6)
			{
				s=s+"5";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn7)
			{
				s=s+"6";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn8)//-
			{
				b=a;
				a=Double.valueOf(s).doubleValue();
				switch(sign)
				 {
						case '+': a=b+a; break;
						case '-': a=b-a; break;
						case '*': a=b*a; break;
					    case '/': a=b/a; break;
				 }
				 s="";
				 s=s+a;
				 input1.setText(s);
				 sign='-';
				 s="";

		    }
		    else if(e.getSource()==btn9)
			{
				s=s+"7";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn10)
			{
				s=s+"8";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn11)
			{
				s=s+"9";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn12)//*
			{
				b=a;
				a=Double.valueOf(s).doubleValue();
				switch(sign)
				{
					case '+': a=b+a; break;
					case '-': a=b-a; break;
					case '*': a=b*a; break;
					case '/': a=b/a; break;
				}
				s="";
		        s=s+a;
				input1.setText(s);
			    sign='*';
				s="";

		    }
		    else if(e.getSource()==btn13)
			{
				s="";
				input1.setText("");
		    }
		    else if(e.getSource()==btn14) //=
			{
				b=a;
			    a=Double.valueOf(s).doubleValue();
				switch(sign)
				{
				   case '+': a=b+a; break;
				   case '-': a=b-a; break;
				   case '*': a=b*a; break;
				   case '/': a=b/a; break;
				}
				s="";
				s=s+a;
			    input1.setText(s);
				sign='a';
				s="";

		    }
		    else if(e.getSource()==btn15)
			{
				s=s+"0";
				input1.setText(s);
		    }
		    else if(e.getSource()==btn16)// /
			{
				b=a;
				a=Double.valueOf(s).doubleValue();
				switch(sign)
				{
					case '+': a=b+a; break;
					case '-': a=b-a; break;
					case '*': a=b*a; break;
					case '/': a=b/a; break;
				}
				s="";
				s=s+a;
	            input1.setText(s);
				sign='/';
				s="";
		    }



		}

	}