public void printMenu() //menu
{
bool done = false, accepted = true;
string temp;
double value;
while (done == false)
{
do
{
Console.WriteLine("Choose an option:");
Console.WriteLine("1. Enter an expression");
Console.WriteLine("2. Set a variable value");
Console.WriteLine("3. Evaluate the expression to a numerical value");
Console.WriteLine("4. Quit");
option = Console.ReadLine(); //get the user's choice
} while ((option != "1") && (option != "2") && (option != "3") && (option != "4"));
if (option == "1") //enter an expression
{
expTree.clearVar(); //clear old variables before starting a new expression
Console.WriteLine("Enter a expression with at most one kind of operator:");
expression = Console.ReadLine(); //read in the user's expression
expTree = new ExpTree(expression); //create a new expression tree with user entered expression
}
else if (option == "2") //set a variable value
{
do
{
accepted = true;
Console.WriteLine("Enter a variable name:");
temp = Console.ReadLine(); //read in the variable name
if ((temp[0] < 'A') || (temp[0] > 'z'))
{
Console.WriteLine("The variable name must start with a letter");
accepted = false;
}
} while (accepted == false);
Console.WriteLine("Enter the variable value:");
value = Convert.ToDouble(Console.ReadLine()); //read in variable value as double
expTree.SetVar(temp, value); //call set var function to add the name and value to variable dictionary
}
else if (option == "3") //evaluate an expression
{
if (expTree.getDictionarySize() > 0) //there are variable values that need to be added to the tree
{
expTree.resetTree(expression);
}
value = expTree.Eval(); //call eval function
Console.WriteLine("The result of the evaluation was: ");
Console.WriteLine(value.ToString()); //print out result of eval function
}
else if (option == "4") //quit
{
done = true;
}
}
}