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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