用java代码写的简易计算器（可以实现基本的加减乘除功能）

package A;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.*;

public class Calcular3 extends JFrame implements ActionListener,MouseListener{
	private int m1=0,n=0;//
	private double m2=0;//运算的数
	private int flag=0;
	JFrame f;
	JPanel p1,p2,p3;
	JTextField t;
	JButton b1[]=new JButton[18];
	String b[]= {"1","2","3","4","5","6","7","8","9","0","清空","退格",".","=","+","-","*","/"};
	public Calcular3(){
		f=new JFrame("计算器");
		t=new JTextField(35);
		p1=new JPanel();
		p2=new JPanel();
		p3=new JPanel();
		f.setBounds(100, 100, 400, 200);
		f.add(p1,BorderLayout.NORTH);
		f.add(p2,BorderLayout.CENTER);
		f.add(p3,BorderLayout.EAST);
		p2.setLayout(new GridLayout(5,3));
		p3.setLayout(new GridLayout(4,1));
		p1.add(t);
		for(int i=0;i<14;i++) {
			b1[i]=new JButton(b[i]);
			p2.add(b1[i]);
			b1[i].addActionListener(this);
		}
		for(int i=14;i<18;i++) {
			b1[i]=new JButton(b[i]);
			p3.add(b1[i]);
			b1[i].addActionListener(this);
		}
		/*for(int i=0;i<18;i++) {
			b1[i].addActionListener(this);
		}*/
		f.setVisible(true);
	}
//实现接口的方法
	public void mouseClicked(MouseEvent e) {
		
	}
	public void mousePressed(MouseEvent e) {
		
	}
	public void mouseReleased(MouseEvent e) {
		
	}
	public void mouseEntered(MouseEvent e) {
		
	}
	public void mouseExited(MouseEvent e) {
		
	}
	public void actionPerformed(ActionEvent e) {
		String str="";
		int i;
		for(i=0;i<=9;i++) {
			if(e.getSource()==b1[i]) {
				if(i==9) {
					n=n*10;
				}else {
					n=n*10+i+1;
				}	
				str=String.valueOf(n);//整形n转换成字符串str
				t.setText(str);//显示到文本框上
			}
		}
		for(i=14;i<18;i++) {//+、-、*、/
			if(e.getSource()==b1[i]) {//匹配运算符
				m1=Integer.parseInt(t.getText());
				if(flag==15) {
					m2=m1+m2;
				}else if(flag==16) {
					m2=m1-m2;
				}else if(flag==17) {
					m2=m1*m2;
				}else if(flag==18) {
					m2=m1/m2;
				}else m2=m1;//若无连续的运算符运算，保存当前数据到m2
				if(i==14)  flag=15;
				else if(i==15)  flag=16;
				else if(i==16)  flag=17;
				else flag=18;
				str=String.valueOf(b[i]);
				t.setText(str);//显示到文本框上
				n=0;//还原，记录下次数据
				break;//找到匹配数据退出循环
			}
		}
		if(e.getSource()==b1[13]) {//=
			m1=Integer.parseInt(t.getText());
			if(flag==15) {
				m2=m2+m1;
			}else if(flag==16) {
				m2=m2-m1;
			}else if(flag==17) {
				m2=m2*m1;
			}else if(flag==18) {
				m2=m2/m1;
			}else m2=m1;
			str=String.valueOf(m2);
			t.setText(str);//显示到文本框上
			n=0;//还原，记录下次数据
			flag=0;//flag还原0，表明没有未处理的运算符
		}
		if(e.getSource()==b1[10]) {//各变量变为0  清空
			m1=0;
			m2=0;
			flag=0;
			n=0;
			t.setText("0");//显示到文本框上
		}
		if(e.getSource()==b1[11]) {//退格
			m1=(int)(Double.parseDouble(t.getText())/10);
			n=m1;
			str=String.valueOf(m1);
			t.setText(str);
		}
		if(e.getSource()==b1[12]) {//小数点
			m1=Integer.parseInt(t.getText());
			str=String.valueOf(m1+b[12]);
			t.setText(str);//显示到文本框上
			int j=0;
			for(i=0;i<=9;i++) {
				if(e.getSource()==b1[i]) {
					j++;
					m2=Math.pow(0.1, j)*Integer.parseInt(b[i]);
					str=String.valueOf(m1+m2);
					t.setText(str);//显示到文本框上
				}
			}
			
		}
	}
//主函数
	public static void main(String[] args) {
		new  Calcular3();
	}

}