public void enter()
{
displayValue[3] = displayValue[2];
displayValue[2] = displayValue[1];
displayValue[1] = displayValue[0];
eventOccurred = CALCULATION_TYPE.enterOccurred;
}
public void subtract()
{
displayValue[0] = (Convert.ToDouble(displayValue[1]) - Convert.ToDouble(displayValue[0])).ToString();
displayValue[1] = displayValue[2];
displayValue[2] = displayValue[3];
displayValue[3] = "0";
eventOccurred = CALCULATION_TYPE.enterOccurred;
}
public void swap()
{
double temp = Convert.ToDouble(displayValue[0]);
displayValue[0] = displayValue[1];
displayValue[1] = temp.ToString();
eventOccurred = CALCULATION_TYPE.calculationOccurred;
}
public void clearAll()
{
for (int i = 0; i < 4; ++i)
{
displayValue[i] = "0";
}
eventOccurred = CALCULATION_TYPE.none;
}
public void exponent()
{
displayValue[0] = (Math.Pow(Convert.ToDouble(displayValue[1]), Convert.ToDouble(displayValue[0]))).ToString();
displayValue[1] = displayValue[2];
displayValue[2] = displayValue[3];
displayValue[3] = "0";
eventOccurred = CALCULATION_TYPE.enterOccurred;
}
public void buildDisplayValue(char c)
{
if (eventOccurred == CALCULATION_TYPE.enterOccurred)
{
eventOccurred = CALCULATION_TYPE.none;
displayValue[0] = c.ToString();
}
else if (eventOccurred == CALCULATION_TYPE.calculationOccurred)
{
eventOccurred = CALCULATION_TYPE.none;
displayValue[3] = displayValue[2];
displayValue[2] = displayValue[1];
displayValue[1] = displayValue[0];
displayValue[0] = c.ToString();
}
else if (displayValue[0][0] == '0' && displayValue[0].Length == 1)
{
displayValue[0] = c.ToString();
}
else
{
displayValue[0] += c.ToString();
}
}