Balance of Power [BOP]

Summary:
This indicator script measures the balance between the bulls and the bears by assessing the ability of each to push price to an extreme level.

Calculation:
The closing price minus the opening price divided by the high price minus the low price.

Developer:
Igor Livshin

Interpretation: 
1. Upwards Trend: When the indicator script is moving upwards, the underlying symbol is in an upwards trend.
2. Downwards Trend: When the indicator script is moving downwards, the underlying symbol is in a downwards trend.
3. Positive Divergence:  When the underlying symbol is moving downwards, but the indicator script is moving upwards, the underlying symbol is likely to reverse direction and move upwards.
4. Negative Divergence:  When the underlying symbol is moving upwards, but the indicator script is moving downwards, the underlying symbol is likely to reverse direction and move downwards.
5. Overbought:  When the underlying symbol is moving upwards, but the indicator script is approaching its upper bound, the underlying symbol is likely to reverse direction and move downwards.
6. Oversold: When the underlying symbol is moving downwards, but the indicator script is approaching its lower bound, the underlying symbol is likely to reverse direction and move upwards.

	_symbolIndex = symbolIndex

	 ' Get the opening prices of the symbol bars, indexed by bar index.
	Define open() As Number = BarOpen(_symbolIndex, barIndex, length)
	 ' Get the highest prices of the symbol bars, indexed by bar index.
	Define high() As Number = BarHigh(_symbolIndex, barIndex, length)
	 ' Get the lowest prices of the symbol bars, indexed by bar index.
	Define low() As Number = BarLow(_symbolIndex, barIndex, length)
	 ' Get the closing prices of the symbol bars, indexed by bar index.
	Define close() As Number = BarClose(_symbolIndex, barIndex, length)
	 ' Use for the calculated Balance of Power.
	Define results(length - 1) As Number
	 ' Calculate the Balance of Power values for the specified bar range.
	For i As Integer = length - 1 To 0 Step -1
		 ' Calculate and assign the Balance of Power value for the current bar.
		results(i) = (close(i) - open(i)) /  (high(i) - low(i))
	Next
	Return results