C#设计一个计算圆面积和周长的类

Question

C#设计一个计算圆面积和周长的类

Answer 1

public class Cal
{
public Cal()
{
}
public Cal(int r)
:this()
{
R = r;
}
public int R { get; set; }
public double Area()
{
return Math.PI* R * R;
}
public double Circ()
{
return 2 * Math.PI * R;
}
}