}// end submitButton_Click
/// <summary>
/// Converts the input string to all lowercase letters and removes all spaces. Then checks if
/// the variables being used have values in their textboxes and that they are correct values.
/// If not, the user is alerted. The variables in the string are replaced with their values.
/// Then, the input string is them converted to postfix format and evaluated.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void submitButton_Click(object sender, EventArgs e)
{
string infix = evaluationBox.Text; // Get the string from the evaluation textbox
System.Diagnostics.Debug.WriteLine(infix);
infix = infix.ToLower(); // Converts all upper case characters in the string to lower case
infix = infix.Replace(" ", string.Empty); // Remove all spaces from the string
System.Diagnostics.Debug.WriteLine(infix);
if (variableCheck(ref infix))
{
System.Diagnostics.Debug.WriteLine(infix);
// Replace all variables with their associated values
infix = replaceVariablesWithValues(infix);
System.Diagnostics.Debug.WriteLine(infix);
//CommandFactory factory = new BasicFactory();
CommandFactory factory = new OptimizedFactory();
// Parse the user's equation from infix into postfix format
Parser parser = new Parser();
List<Command> postfix = parser.infixToPostfix(infix, factory);
System.Diagnostics.Debug.WriteLine(infix);
// Evaluate the postfix format equation
Evaluator evaluator = new Postfix();
int result = evaluator.evaluatePostfix(postfix);
lblEqual.Visible = true;
lblResult.Text = result.ToString();
}// end if
}// end submitButton_Click