internal string pullValue(Operator op)
{
//Pop 2 values and perform operation
try
{
value1 = rpnStack.Pop();
value2 = rpnStack.Pop();
}
catch (InvalidOperationException)
{
//If stack has less than 2 values, return error and clear
clear();
return "ERROR";
}
//Do operation
value1 = op.perform(value1, value2);
//Push back onto stack
rpnStack.Push(value1);
//display computed value, note: in this implementation it will already be pushed before displaying
return value1.ToString();
}
