Add Zero line to chart study

Pete,

Could you help me add a Zero line to my chart study….

declare lower;

#INPUTS
input Smoother = 5;
input SupResPeriod = 50;
input SupResPercentage = 100;
input PricePeriod = 16;
input ob = 200;
input os = -200;
input showColorBars = no; #COLOR BARS
input showDynamics = no; #Dynamic zones
input showOBOS = yes; #Show OB/OS

#LOGIC
def nn = Smoother;
def ys1 = (high + low + close * 2) / 4;
def rk3 = ExpAverage(ys1, nn);
def rk4 = StDev(ys1, nn);
def rk5 = (ys1 – rk3) * 200 / rk4;
def rk6 = ExpAverage(rk5, nn);
def up = ExpAverage(rk6, nn);
def down = ExpAverage(up, nn);
def Oo = If(up < down, up, down);
def Hh = Oo;
def Ll = If(up < down, down, up);
def Cc = Ll;

def Lookback = SupResPeriod;
def PerCent = SupResPercentage;
def Pds = PricePeriod;

def C3 = CCI(length = Pds);

def Osc = C3;
def Value1 = Osc;
def Value2 = Highest(Value1, Lookback);
def Value3 = Lowest(Value1, Lookback);
def Value4 = Value2 – Value3;
def Value5 = Value4 * (PerCent / 100);
def ResistanceLine = Value3 + Value5;
def SupportLine = Value2 – Value5;

#CUSTOM CANDLES
def cUpO;
def cUpH;
def cUpL;
def cUpC;
if up > down
then {
cUpO = oo;
cUpH = hh;
cUpL = ll;
cUpC = cc;
} else {
cUpO = Double.NaN;
cUpH = Double.NaN;
cUpL = Double.NaN;
cUpC = Double.NaN;
}

def cDnO;
def cDnH;
def cDnL;
def cDnC;
if up < down
then {
cDnO = Oo;
cDnH = Hh;
cDnL = Ll;
cDnC = Cc;
} else {
cdnO = Double.NaN;
cdnH = Double.NaN;
cdnL = Double.NaN;
cdnC = Double.NaN;
}

AddChart(high = cUpH, low = cUpL, open = cUpC, close = cUpO, type = ChartType.CANDLE, COLOR.GREEN);
AddChart(high = cDnH, low = cDnL, open = cDnO, close = cDnC, type = ChartType.CANDLE, COLOR.RED);
AddChart(high = cUpH, low = cUpL, open = cUpO, close = cUpC, type = ChartType.CANDLE, growcolor = COLOR.GREEN);
AddChart(high = cDnH, low = cDnL, open = cDnC, close = cDnO, type = ChartType.CANDLE, growcolor = COLOR.RED);

#COLORBARS
AssignPriceColor(if showColorBars then
if Oo > Cc then COLOR.RED else if up > down then COLOR.GREEN
else COLOR.RED
else
COLOR.CURRENT
);

#PLOTS
plot pResistanceLine = ResistanceLine;
pResistanceLine.SetHiding(!showDynamics);

plot pSupportLine = SupportLine;
pSupportLine.SetHiding(!showDynamics);

def UpShape = if up > ob and up > down then highest(up,1) + 20 else if up > ob and up < down then highest(down,1) + 20 else Double.NaN;

def DownShape = if down < os and up > down then lowest(down,1) – 20 else if
down < os and up < down then lowest(up,1) – 20 else Double.NaN;

def sState = if !isNan(UpShape) then 100 else if !isNan(DownShape) then -100 else sState[1];

plot pUP = UpShape;
pUP.SetPaintingStrategy(PaintingStrategy.TRIANGLES);
pUP.SetDefaultColor(Color.CYAN);
pUP.SetLineWeight(1);

plot pDown = DownShape;
pDown.SetPaintingStrategy(PaintingStrategy.TRIANGLES);
pDown.SetDefaultColor(Color.CYAN);
pDown.SetLineWeight(1);
;

plot pOB = OB;
pOB.SetHiding(!showOBOS);

plot pOS = OS;
pOS.SetHiding(!showOBOS);