using System; public class Program { static void Main(string[] args) { Console.Write("A = "); double a = double.Parse(Console.ReadLine()); Console.Write("OP = "); char op = char.Parse(Console.ReadLine()); Console.Write("B = "); double b = double.Parse(Console.ReadLine()); bool ok = true; double res = 0; switch (op) { case '+': res = a + b; break; case '-': res = a - b; break; case '*': res = a * b; break; case '/': case ':': res = a / b; break; default: ok = false; break; } if (ok) { Console.WriteLine("{0} {1} {2} = {3}", a, op, b, res); } else { Console.WriteLine("Операция не определена"); } } }