MQL4 - Stochastic

#define BARS_TO_ANALYSE 100;

function stocasticSignal(){

string signal;

for(int a=0;a<BARS_TO_ANALYSE;a++)
   {
      mainLine=iStochastic(0,0,5,3,3,MODE_SMA,0,MODE_MAIN,a);
      prevMainLine=iStochastic(0,0,5,3,3,MODE_SMA,0,MODE_MAIN,a+1);
      signalLine=iStochastic(0,0,5,3,3,MODE_SMA,0,MODE_SIGNAL,a);
      prevSignalLine=iStochastic(0,0,5,3,3,MODE_SMA,0,MODE_SIGNAL,a+1);
        
	 if(prevMainLine <prevSignalLine && mainLine> signalLine){
        signal = "BUY";
	 }
     if(prevMainLine>prevSignalLine && mainLine < signalLine){
        signal = "SELL";     
	 }
   } return signal;                                                                                                                                              
}