private static void Menu() { double firstValue = 0; double secondValue = 0; double radius = 0; double result; Calculator calc = new Calculator(); Console.WriteLine("This program could perform several actions:"); Console.WriteLine("\t1. Calculate sum of two numbers;"); Console.WriteLine("\t2. Calculate difference of two numbers;"); Console.WriteLine("\t3. Calculate product of two numbers;"); Console.WriteLine("\t4. Calculate quotient of two numbers;"); Console.WriteLine("\t5. Calculate area of circle using radius;"); Console.WriteLine("Please input number represents menu item: "); string menuItem = Console.ReadLine(); switch (menuItem) { case "1": Console.WriteLine("Input parameters for calculating:\n"); InputTwoParametrs(out firstValue, out secondValue); result = calc.Addition(firstValue, secondValue); Console.WriteLine($"Sum of A={firstValue} and B={secondValue} equals to {result}"); break; case "2": Console.WriteLine("Input parameters for calculating:\n"); InputTwoParametrs(out firstValue, out secondValue); result = calc.Subtraction(firstValue, secondValue); Console.WriteLine($"Difference of A={firstValue} and B={secondValue} equals to {result}"); break; case "3": Console.WriteLine("Input parameters for calculating:\n"); InputTwoParametrs(out firstValue, out secondValue); result = calc.Multiplication(firstValue, secondValue); Console.WriteLine($"Product of A={firstValue} and B={secondValue} equals to {result}"); break; case "4": Console.WriteLine("Input parameters for calculating:\n"); InputTwoParametrs(out firstValue, out secondValue); result = calc.Division(firstValue, secondValue); Console.WriteLine($"Quotient of A={firstValue} and B={secondValue} equals to {result}"); break; case "5": Console.WriteLine("Input radius to perform calculation:\n"); radius = InputValue(); Console.WriteLine($"Area of circle with radius R={radius} equals to S={calc.AreaOfCircle(radius)}"); break; default: Console.WriteLine("Input unresolved. Please try again!\n\n"); bRepeateFlag = true; return; } Console.WriteLine("Calculations done! Want to calculate smth again? (Y,N)"); if (Console.ReadKey().Key == ConsoleKey.Y) { bRepeateFlag = true; Console.WriteLine("\n"); } else { bRepeateFlag = false; } }