C# 中的类和静态变量
静态变量用于定义常量,因为无需创建实例,只需调用类即可检索其值。静态变量可以在成员函数或类定义之外进行初始化。你也可以在类定义内初始化静态变量。
示例
using System; namespace StaticVarApplication { class StaticVar { public static int num; public void count() { num++; } public int getNum() { return num; } } class StaticTester { static void Main(string[] args) { StaticVar s1 = new StaticVar(); StaticVar s2 = new StaticVar(); s1.count(); s1.count(); s1.count(); s2.count(); s2.count(); s2.count(); Console.WriteLine("Variable num for s1: {0}", s1.getNum()); Console.WriteLine("Variable num for s2: {0}", s2.getNum()); Console.ReadKey(); } } }
输出
Variable num for s1: 6 Variable num for s2: 6
类变量是对象(从设计的角度)的属性,并且出于封装目的,将它们设置为私有。只能使用公共成员函数访问这些变量。
我们来看一个示例 -
示例
using System; namespace BoxApplication { class Box { private double length; // Length of a box private double breadth; // Breadth of a box private double height; // Height of a box public void setLength( double len ) { length = len; } public void setBreadth( double bre ) { breadth = bre; } public void setHeight( double hei ) { height = hei; } public double getVolume() { return length * breadth * height; } } class Boxtester { static void Main(string[] args) { Box Box1 = new Box(); // Declare Box1 of type Box Box Box2 = new Box(); double volume; // Declare Box2 of type Box // box 1 specification Box1.setLength(6.0); Box1.setBreadth(7.0); Box1.setHeight(5.0); // box 2 specification Box2.setLength(12.0); Box2.setBreadth(13.0); Box2.setHeight(10.0); // volume of box 1 volume = Box1.getVolume(); Console.WriteLine("Volume of Box1 : {0}" ,volume); // volume of box 2 volume = Box2.getVolume(); Console.WriteLine("Volume of Box2 : {0}", volume); Console.ReadKey(); } } }
输出
Volume of Box1 : 210 Volume of Box2 : 1560
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