This code snippet demonstrates how to implement a Relative Strength Index (RSI) indicator in ProBuilder, which can be displayed with or without its traditional 0-100% scale. The RSI is a popular momentum oscillator used in technical analysis that measures the speed and change of price movements.

// RSI custom (with & without scale)
// (https://www.prorealcode.com/topic/indicatore-rsi/#post-51250)
// (https://www.investopedia.com/terms/r/rsi.asp)
//
// p = 14 //periods
p = max(1,min(p,999)) //1 - 999
Ob = 70 //OverBought
Os = 100 - Ob //OverSold
Middle = 50 //mean line
//
// r = 0
// g = 0
// b = 255
// t = 255
//
// Bullish = MAX(0, CLOSE - CLOSE[1])
// Bearish = MAX(0, CLOSE[1] - CLOSE)
//
// mmBullish = WILDERAVERAGE[p](Bullish)
// mmBearish = WILDERAVERAGE[p](Bearish)
//
// RS = mmBullish / mmBearish
IF ScaleEnabled THEN
    myRSI = 100 - (100 / (1 + RS)) //scale
ELSE
    MyRSI = RS //no scale
    t = 0
    Ob = MyRSI
    Os = MyRSI
    Middle = MyRSI
ENDIF
//
// RETURN MyRSI AS "Rsi",Os coloured(r,g,b,t) AS "Os",Ob coloured(r,g,b,t) AS "Ob", Middle coloured(r,g,b,t) as "Mid"

The code snippet above is structured to calculate and display the RSI in two modes: scaled and unscaled. Here’s a breakdown of its components:

• Parameter Initialization: The period p is set and constrained between 1 and 999. The overbought (Ob) and oversold (Os) levels are defined, along with a middle line (Middle).
• Color Settings: Variables for color settings (r, g, b, t) are initialized but not altered in the snippet provided.
• Calculation of Bullish and Bearish Values: These are calculated by comparing the current close price with the previous close price. The Wilder’s Moving Average is applied to both.
• RS Calculation: The Relative Strength (RS) is calculated by dividing the average gain (mmBullish) by the average loss (mmBearish).
• Conditional RSI Calculation: If ScaleEnabled is true, the traditional RSI formula is used. If false, the RSI is represented by the RS value itself, affecting the display of overbought, oversold, and middle lines to match the RS value.
• Output: The RSI value and the levels (Os, Ob, Middle) are returned, with color settings applied based on the initial color variables.

This example is useful for understanding conditional statements and custom indicator development in ProBuilder.