构造函数属性

using System;
public class Square
{
private int sidelong;
 public Square()
 {
 Console.WriteLine ("我没有参数.");
 }
 public Square(int sidelong)
 {
 this.sidelong=sidelong;
 }
 public int Setsidelong(int sidelong)
 {
     this.sidelong=sidelong;
  return sidelong;
 }
 public int Getsidelong(int sidelong)
 {
 return sidelong;
 }
 public void Print()
 {
 Console.WriteLine ("当前正方形的边长是：{0}",sidelong);
 }

}
class Square_Test
{
 public static void Main()
 {
 Square s1=new Square ();
  s1.Setsidelong (4);
  s1.Print ();
  Square s2=new Square ();
 }
}