private static void Main(string[] args)
{
//Initialized objects and variables
BinaryExpression ExpressionTree = null;
bool IsValidExpression = false;
bool ResultIsValid = false;
MyExpressionVisitor myExpressionVisitor = new MyExpressionVisitor();
Validation ValidateInput = new Validation();
CalculateExpression GoToCalculation = new CalculateExpression();
//Prompts the user until valid expression
do
{
var StringExpression = GoToCalculation.PromptUser();
ResultIsValid = ValidateInput.IsValid(StringExpression, IsValidExpression);
//Each character in the expression is being validated one at a time
if (ResultIsValid)
{
ExpressionTree = GoToCalculation.CalculateValidExpression(StringExpression, ExpressionTree, myExpressionVisitor);
try
{
var results = Expression.Lambda(ExpressionTree).Compile().DynamicInvoke();
Console.ForegroundColor = ConsoleColor.Green;
Console.WriteLine($"The Reverse Polish Notation of this expression is: {results:f}");
Console.ResetColor();
IsValidExpression = true;
}
catch
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine($"\n{StringExpression} is NOT a valid Reverse Polish Notation expression, please enter a valid expression");
Console.ResetColor();
IsValidExpression = false;
}
}
} while (!IsValidExpression);
Console.ReadKey();
}
/// <summary>
/// This method takes in parameters after validation is complete
/// Of ValidExpression, ExpressionTree, And using MyExpressionVisitor Class
/// This allows the ExpressionTree Variable to access the MyExpressionVisitor class
/// To add to the stack of binary expressions and constants
/// And returns the ExpressionTree complete expression
/// </summary>
/// <param name="ValidExpression"></param>
/// <param name="ExpressionTree"></param>
/// <param name="myExpressionVisitor"></param>
/// <returns></returns>
public BinaryExpression CalculateValidExpression(string ValidExpression, BinaryExpression ExpressionTree, MyExpressionVisitor myExpressionVisitor)
{
foreach (var token in ValidExpression.Split(' '))
{
//Checks for operand
if (double.TryParse(token, out var result))
{
ExpressionTree = (BinaryExpression)myExpressionVisitor.Visit(Expression.Constant(result));
}
//Operator otherwise
else
{
ExpressionTree = (BinaryExpression)myExpressionVisitor.Visit(Expression.Constant(token));
}
}
return(ExpressionTree);
}
