Donchian Channel Upper [DCU]

Summary:
This indicator script measures the highest  price of an underlying symbol in a specified number of periods.

Calculation:
The highest high in a specified number of periods of the underlying symbol.

Developer:
Richard Donchian

Interpretation: 
1. Resistance: When the underlying symbol is moving upwards towards the indicator script, the underlying symbol is likely to reverse direction and move downwards.
2. Resistance Broken: When the underlying symbol breaks resistance by crossing above the indicator script, the underlying symbol is likely to continue moving upwards.

	 ' Assign the parameter to script variables.
	_symbolIndex = symbolIndex
	_periods = periods

	 ' Get the highest prices of the symbol, indexed by bar index. 
	Define high() As Number = BarHigh(_symbolIndex, barIndex, length + _periods)
	Define max As Number
	 ' Use for the calculated Donchian Channel Upper values, indexed by bar index.
	Define results(length - 1) As Number
	 ' Calculate the Donchian Channel Upper values for the specified bar range.
	For i As Integer = length - 1 To 0 Step -1
		max = 0
		 ' Calculate the Donchian Channel Upper value for the current bar.
		For j As Integer = i + _periods - 1 To i Step -1
			If (high(j) > max) Then
				max = high(j)
			End If
		Next
		results(i) = max
	Next
	Return results