static void Main() { Console.WriteLine("Welcome to the calculator app. Please type the 2 values to operate on"); Console.WriteLine("Then, type the operator you wish to use."); while (true) { string stuf1 = Console.ReadLine(); //always need to define types for variables string operato1 = Console.ReadLine(); string stuf2 = Console.ReadLine(); int arg1 = Convert.ToInt32(stuf1); int arg2 = Convert.ToInt32(stuf2); switch (operato1) { case "+": { Console.WriteLine(Calculator.Addition(arg1, arg2)); continue; } case "-": { Console.WriteLine(Calculator.Subtraction(arg1, arg2)); continue; } case "*": { Console.WriteLine(Calculator.Multiplication(arg1, arg2)); continue; } case "/": { Console.WriteLine(Calculator.Divison(arg1, arg2)); continue; } case "end": { break; } } } }