static void Main(string[] args)
{
L1 : Console.WriteLine("choose the number:1 for rectangle, 2 for square and 3 for triangle");
int choice = Convert.ToInt32(Console.ReadLine());
switch (choice)
{
case 1:
Console.WriteLine("enter the length and width in order:");
Rectangle shape1 = new Rectangle(Convert.ToDouble(Console.ReadLine()), Convert.ToDouble(Console.ReadLine()));
if (shape1.legal())
{
Console.WriteLine("legal" + "\n and the area is " + shape1.area_calculating());
}
else
{
Console.WriteLine("illegal" + "\n therefore, the area can not be calculated");
}
break;
case 2:
Console.WriteLine("enter the side_length:");
Square shape2 = new Square(Convert.ToDouble(Console.ReadLine()));
if (shape2.legal())
{
Console.WriteLine("legal" + "\n and the area is " + shape2.area_calculating());
}
else
{
Console.WriteLine("illegal" + "\n therefore, the area can not be calculated");
}
break;
case 3:
Console.WriteLine("enter the three sides in order:");
Triangle shape3 = new Triangle(Convert.ToDouble(Console.ReadLine()), Convert.ToDouble(Console.ReadLine()), Convert.ToDouble(Console.ReadLine()));
if (shape3.legal())
{
Console.WriteLine("legal" + "\n and the area is " + shape3.area_calculating());
}
else
{
Console.WriteLine("illegal" + "\n therefore, the area can not be calculated");
}
break;
default:
goto L1;
}
Console.ReadKey();
}
