java 简单的计算器程序实例代码
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2023-12-17 09:55:58
java 简单的计算器程序
实现实例:
import java.awt.*;
import java.awt.event.*;
import javax...
java 简单的计算器程序
实现实例:
import java.awt.*; import java.awt.event.*; import javax.swing.*; public class calculator { public static void main(string[] args) { eventqueue.invokelater(new runnable() { public void run() { calculatorframe frame = new calculatorframe(); frame.setdefaultcloseoperation(jframe.exit_on_close); frame.setvisible(true); } }); } } /** * a frame with a calculator panel. */ class calculatorframe extends jframe { public calculatorframe() { settitle("calculator"); calculatorpanel panel=new calculatorpanel(); add(panel); pack(); } } class calculatorpanel extends jpanel { private jbutton display; private jpanel panel; private double result; private string lastcommand; private boolean start; public calculatorpanel() { setlayout(new borderlayout()); result=0; lastcommand="="; start=true; // add the display display=new jbutton("0"); display.setenabled(false); add(display,borderlayout.north); actionlistener insert=new insertaction(); actionlistener command=new commandaction(); panel=new jpanel(); panel.setlayout(new gridlayout(4,4)); addbutton("7", insert); addbutton("8", insert); addbutton("9", insert); addbutton("/", command); addbutton("4", insert); addbutton("5", insert); addbutton("6", insert); addbutton("*", command); addbutton("1", insert); addbutton("2", insert); addbutton("3", insert); addbutton("-", command); addbutton("0", insert); addbutton(".", insert); addbutton("=", command); addbutton("+", command); add(panel, borderlayout.center); } private void addbutton(string label,actionlistener listener) { jbutton button=new jbutton(label); button.addactionlistener(listener); panel.add(button); } /** * this action inserts the button action string to the end of the display text. */ private class insertaction implements actionlistener { public void actionperformed(actionevent event) { string input=event.getactioncommand(); if(start) { display.settext(""); start=false; } display.settext(display.gettext()+input); } } /** * this action executes the command that the button action string denotes. */ private class commandaction implements actionlistener { public void actionperformed(actionevent event) { string command=event.getactioncommand(); if(start) { if (command.equals("-")) { display.settext(command); start = false; } else lastcommand = command; }else { calculate(double.parsedouble(display.gettext())); lastcommand=command; start=true; } } } /** * carries out the pending calculation. * @param x the value to be accumulated with the prior result. */ public void calculate(double x) { if (lastcommand.equals("+")) result += x; else if (lastcommand.equals("-")) result -= x; else if (lastcommand.equals("*")) result *= x; else if (lastcommand.equals("/")) result /= x; else if (lastcommand.equals("=")) result = x; display.settext("" + result); } }
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