public List<string> StringInterpreter(string equation)
{
int x = 1;
List<string> list = new List<string>() { };
Regex regex = new Regex(@"(\d*\.?\d*)");
Regex regex1 = new Regex(@"[*+/-]");
MatchCollection matches = regex.Matches(equation);
MatchCollection matches1 = regex1.Matches(equation);
foreach (Match match in matches)
{
list.Add(Convert.ToString(match));
}
foreach (Match match in matches1)
{
list.Insert(x, Convert.ToString(match));
x += 3;
}
return list;
}
/// <summary>
/// Finds the first instance of currentOperator (i.e. '+'), takes the operands on the left and right
/// to the operator and builds an Expression instance (i.e. AddExpression in case of '+').
/// </summary>
/// <param name="expression">A list containing numbers, operators and expressions.</param>
/// <param name="currentOperator">The symbol of the current operator to be processed.</param>
private static void CreateExpression(List<dynamic> expression, char currentOperator)
{
int operatorIndex = expression.IndexOf(currentOperator);
Expression operation;
dynamic leftOperand, rightOperand;
try
{
if (expression.ElementAt(operatorIndex - 1) is double)
{
leftOperand = new NumberExpression(expression.ElementAt(operatorIndex - 1));
}
else if (expression.ElementAt(operatorIndex - 1) is Expression)
{
leftOperand = expression.ElementAt(operatorIndex - 1);
}
else
{
throw new ArgumentException("Invalid expression string.");
}
if (expression.ElementAt(operatorIndex + 1) is double)
{
rightOperand = new NumberExpression(expression.ElementAt(operatorIndex + 1));
}
else if (expression.ElementAt(operatorIndex + 1) is Expression)
{
rightOperand = expression.ElementAt(operatorIndex + 1);
}
else
{
throw new ArgumentException("Invalid expression string.");
}
}
catch (Exception ex)
{
throw new ArgumentException("Invalid expression string.");
}
switch (currentOperator)
{
case '+':
operation = new AddExpression(leftOperand, rightOperand);
break;
case '-':
operation = new SubtractExpression(leftOperand, rightOperand);
break;
case '*':
operation = new MultiplyExpression(leftOperand, rightOperand);
break;
case '/':
operation = new DivideExpression(leftOperand, rightOperand);
break;
default:
operation = new NumberExpression(0);
break;
}
expression.RemoveAt(operatorIndex + 1);
expression.RemoveAt(operatorIndex);
expression.RemoveAt(operatorIndex - 1);
expression.Insert(operatorIndex - 1, operation);
}
