Help in coding an EA

I'm a new MQL4 EA coder, for OZFX system I want to change the buy/sell rule based on AC ( Accelerate Oscillator ) is red or green ( value up or down ) not above or below 0 level like the original rule, can help me to do that ? I don't know how to get AC value is up or down
Someone please post that code.

//1. Acceleration/Deceleration — AC

extern int piac=0; //Indicator period



//Buy: if the indicator is above zero and 2 consecutive columns are green or if the indicator is below zero and 3 consecutive columns are green
//Sell: if the indicator is below zero and 2 consecutive columns are red or if the indicator is above zero and 3 consecutive columns are red

if ((iAC(NULL,piac,0)>=0&&iAC(NULL,piac,0)>iAC(NULL,piac,1)&&iAC(NULL,piac,1)>iAC(NULL,piac,2))||(iAC(NULL,piac,0)<=0&&iAC(NULL,piac,0)>iAC(NULL,piac,1)&&iAC(NULL,piac,1)>iAC(NULL,piac,2)&&iAC(NULL,piac,2)>iAC(NULL,piac,3)))
{signal=1;} \buy

if ((iAC(NULL,piac,0)<=0&&iAC(NULL,piac,0)<iAC(NULL,piac,1)&&iAC(NULL,piac,1)<iAC(NULL,piac,2))||(iAC(NULL,piac,0)>=0&&iAC(NULL,piac,0)<iAC(NULL,piac,1)&&iAC(NULL,piac,1)<iAC(NULL,piac,2)&&iAC(NULL,piac,2)<iAC(NULL,piac,3)))
{signal=-1;} \sell

thank you