Question

用C#编写一个程序，通过键盘输入圆的半径，计算圆的面积和周长

Answer 1

string x = Console.ReadLine();
double r = Convert.ToDouble(x);
Console.WriteLine("圆的面积是：" + Convert.ToString(Math.PI * r * r));
Console.WriteLine("圆的周长是：" + Convert.ToString(Math.PI * 2 * r));
Console.ReadKey();

Answer 2

class Program
{
static void Main(string[] args)
{
double r=0,c,s;
Console.WriteLine("Please Enter The R:");
try
{
r = Convert.ToDouble(Console.ReadLine());
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
c = Math.PI * 2 * r;
s = Math.PI * r * r;
Console.WriteLine("The Perimeter of The Circle is {0},The Area of The Circle is {1}", c, s);
Console.ReadLine();
}

}