packagedemo.java

java程序设计教程的源码

//【例3-11】  包的创建（package的使用）。
//程序清单3-11:  PackageDemo.java
package com.comsoft.ch03;//创建包

public class PackageDemo {// 主类
	public static void main(String args[]) {
		int a = 5, b = 5;
		Math math = new Math();// 对同一包中的类Math实例化
		System.out.println("math.add(" + a + "," + b + ") = " + math.add(a, b));
		System.out.println("math.subtract(" + a + "," + b + ") = "
				+ math.subtract(a, b));
		System.out.println("math.multiply(" + a + "," + b + ") = "
				+ math.multiply(a, b));
		System.out.println("math.divide(" + a + "," + b + ") = "
				+ math.divide(a, b));
	}
}

class Math {// 默认类
	public double add(double x, double y) {
		return x + y;
	}

	public double subtract(double x, double y) {
		return x - y;
	}

	public double multiply(double x, double y) {
		return x * y;
	}

	public double divide(double x, double y) {
		return x / y;
	}
}