public static void Main()
Console.WriteLine("1. Sumar a + b");
Console.WriteLine("2. Imprimir desde 1 hasta N");
Console.WriteLine("3. Calcular perimetro de circulo");
Console.WriteLine("0. Salir");
Console.Write("Ingrese una opcion: ");
opcion = Convert.ToInt16(Console.ReadLine());
Console.Write("Ingrese a: ");
int a = Convert.ToInt16(Console.ReadLine());
Console.Write("Ingrese b: ");
int b = Convert.ToInt16(Console.ReadLine());
Console.WriteLine("La suma es: {0}", suma);
Console.Write("Ingrese n: ");
int n = Convert.ToInt16(Console.ReadLine());
Console.Write("{0} ", i);
Console.Write("Ingrese diametro: ");
int d = Convert.ToInt16(Console.ReadLine());
double perimetro = 3.1416 * d;
Console.WriteLine("El perimetro es: {0}", perimetro);