Java是现在很受欢迎的编程语言，很多企业开发项目都会使用java，java能够应用在各个领域，利用java还能开发出我们想要的项目，那用java实现加减乘除运算怎么弄?下面来我们就来给大家讲解一下。
1、思路
(1)实现四个方法，分别实现加减乘除四个功能。(一个方法实现一个功能，原子性);
(2)用scanner实现键盘交互(这里我们实现的是两个整数之间的加减乘除，用nextInt()函数获取整数，用next().charAt(0)获取我们输入的第一个字符);
(3)用switch进行+、-、*、/的判断选择，调用相应的方法实现两个整数间的加减乘除运算。
2、Java代码
package com.yy.method;
import java.util.Scanner;
public class calculate
{
public static void main(String[] args)
{
Scanner scanner = new Scanner(System.in);
System.out.println("请输入："); //3 * 5
int x = scanner.nextInt();
char c = scanner.next()
.charAt(0); //读入控制台输入的第一个字符
int y = scanner.nextInt();
switch (c)
{
case '+':
sum(x, y);
break;
case '-':
sub(x, y);
break;
case '*':
mul(x, y);
break; //15
case '/':
div(x, y);
break;
}
}
public static void sum(int a, int b)
{
System.out.println(a + b);
}
public static void sub(int a, int b)
{
System.out.println(a - b);
}
public static void mul(int a, int b)
{
System.out.println(a * b);
}
public static void div(int a, int b)
{
System.out.println(a / b);
}
}Java如何实现实现一个简单计算器?
先来看看界面效果：
源码如下：
package test1;
import java.awt.Frame;
import java.awt.TextField;
import java.awt.Button;
import java.awt.Panel;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class calculate
{
TextField tfResult;
Button btNum[], btOper[], btPoint, btEqual, btBack, btSqrt, btPingfang, btLifang;
int num1, num2; //操作数
char oper; //操作符
boolean isNum; //代表数字标志位
public void init()
{
Frame f;
tfResult = new TextField();
btNum = new Button[10]; //数组对象
for (int i = 0; i <= 9; i++)
{
btNum[i] = new Button(i + "");
}
btOper = new Button[4];
btOper[0] = new Button("+");
btOper[1] = new Button("-");
btOper[2] = new Button("*");
btOper[3] = new Button("/");
btPoint = new Button(".");
btEqual = new Button("=");
btBack = new Button("Backspace");
btSqrt = new Button("Sqrt");
btPingfang = new Button("2");
btLifang = new Button("3");
f = new Frame("小羊羔的计算器！");
f.setSize(300, 300);
//放置组件
f.add(tfResult, "North");
Panel panel = new Panel();
f.add(panel, "Center");
GridLayout gl = new GridLayout(5, 4);
panel.setLayout(gl);
panel.add(btNum[1]);
panel.add(btNum[2]);
panel.add(btNum[3]);
panel.add(btOper[0]);
panel.add(btNum[4]);
panel.add(btNum[5]);
panel.add(btNum[6]);
panel.add(btOper[1]);
panel.add(btNum[7]);
panel.add(btNum[8]);
panel.add(btNum[9]);
panel.add(btOper[2]);
panel.add(btNum[0]);
panel.add(btPoint);
panel.add(btEqual);
panel.add(btOper[3]);
panel.add(btBack);
panel.add(btSqrt);
panel.add(btPingfang);
panel.add(btLifang);
f.setVisible(true);
//注册监听
f.addWindowListener(new MyWinLis());
//数字按钮注册监听
MyNumLis mnl = new MyNumLis();
for (int i = 0; i <= 9; i++)
btNum[i].addActionListener(mnl);
//操作符按钮注册监听
MyOperLis mol = new MyOperLis();
for (int j = 0; j <= 3; j++)
btOper[j].addActionListener(mol);
//等号按钮注册监听
MyEqualLis mel = new MyEqualLis();
btEqual.addActionListener(mel);
//删除按钮注册监听
MyBackLis mbl = new MyBackLis();
btBack.addActionListener(mbl);
//开根号按钮注册监听
MySqrtLis msl = new MySqrtLis();
btSqrt.addActionListener(msl);
//平方按钮注册监听
MyPingfangLis mpl = new MyPingfangLis();
btPingfang.addActionListener(mpl);
//百分号注册监听
MyLifangLis mll = new MyLifangLis();
btLifang.addActionListener(mll);
}
//定义监听器类
class MyNumLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
String t = e.getActionCommand();
String s = tfResult.getText();
if (isNum == false)
tfResult.setText(t);
else
tfResult.setText(s + t);
isNum = true;
}
}
class MySqrtLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
double t = Double.parseDouble(tfResult.getText());
tfResult.setText(Math.sqrt(t) + "");
isNum = false;
}
}
class MyPingfangLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
num1 = Integer.parseInt(tfResult.getText());
tfResult.setText(num1 * num1 + "");
}
}
class MyLifangLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
num1 = Integer.parseInt(tfResult.getText());
tfResult.setText(num1 * num1 * num1 + "");
}
}
class MyOperLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
num1 = Integer.parseInt(tfResult.getText()); //转化为INT
oper = e.getActionCommand()
.charAt(0);
isNum = false;
}
}
class MyEqualLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
int result = 0;
isNum = false;
num2 = Integer.parseInt(tfResult.getText());
switch (oper)
{
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
result = num1 / num2;
break;
}
tfResult.setText(result + "");
}
}
class MyBackLis implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
tfResult.setText("");
isNum = false;
}
}
class MyWinLis extends WindowAdapter
{
public void windowClosing(WindowEvent e)
{
e.getWindow()
.setVisible(false);
e.getWindow()
.dispose();
System.exit(0);
}
}
public static void main(String[] args)
{
// TODO Auto-generated method stub
new calculate()
.init();
}
}11×5=?界面如下：
一个简单计算器就这样利用java开发出来了，其实java开发项目很简单，只要我们理清逻辑，写好代码，一般不会有难度!最后大家如果想要了解更多java实例知识，敬请关注奇Q工具网。
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