static void Main(string[] args) { double memory = 0; string input_2 = ""; Operations oper = new Operations(); Console.WriteLine("Calculator\n\tOptions\nAddition\tA\nSubstracion\tB\nMultiplication\tC\nDivision\tD\nSquare root\tE\nTotal\t\tF\nClear memory\tG\nExit\t\tH"); Console.Write("Insert a value: "); string input = Console.ReadLine(); Console.Write("Choose a option: "); string operation = Console.ReadLine(); if (double.TryParse(input, out double number1)) { while (operation != "H") { if (operation == "E") { memory = oper.Sqrt(number1); number1 = memory; } else if (operation == "G") { number1 = 0; Console.WriteLine("Cleaned"); } else if (operation != "F") { Console.Write("Insert other value: "); input_2 = Console.ReadLine(); } if (double.TryParse(input_2, out double number2) && operation != "G") { if (operation == "A") { memory = oper.Addition(number1, number2); number1 = memory; } else if (operation == "B") { memory = oper.Substraction(number1, number2); number1 = memory; } else if (operation == "C") { memory = oper.Multiplication(number1, number2); number1 = memory; } else if (operation == "D") { memory = oper.Division(number1, number2); number1 = memory; } } else { if (operation != "F" && !(operation == "G")) { Console.WriteLine("ERROR: You can't insert a string"); Environment.Exit(0); } } if (operation == "F") { Console.WriteLine("Total: " + number1); } else if (operation != "G") { Console.WriteLine("Current total: " + memory); } Console.Write("Choose a option: "); operation = Console.ReadLine(); } } else { Console.WriteLine("ERROR: You can't insert a string"); } }