What is meaning of these codes?

[KSforex]

Hello

What is meaning of these codes? 

I don't understand Red and bold parts.

1- what is variables started with _ ?

2- what is _mtfCall ?

3- what is meaning of this statement : double PP=(  )? : ;

If possible, please send me documents or references to understand these codes. 

MACDHistB1[i]=(MACDHist[i]>0 && MACDHist[i+1]>MACDHist[i])?MACDHist[i]:0;

double PP=(_Digits==5 || _Digits==3 )?_Point*10:_Point;

#define _mtfCall(_buff,_ind) iCustom(NULL,TimeFrame,indicatorFileName,PERIOD_CURRENT,........., _buff,_ind)

[William Roeder]

1. Variable names that start with an underscore.
   
2. A macro. Macro substitution (#define)
3. Ternary Operator ?:

[Koros Jafarzadeh]

KSforex:

Hello

What is meaning of these codes? 

I don't understand Red and bold parts.

1- what is variables started with _ ?

2- what is _mtfCall ?

3- what is meaning of this statement : double PP=(  )? : ;

If possible, please send me documents or references to understand these codes. 

MACDHistB1[i]=(MACDHist[i]>0 && MACDHist[i+1]>MACDHist[i])?MACDHist[i]:0;

double PP=(_Digits==5 || _Digits==3 )?_Point*10:_Point;

#define _mtfCall(_buff,_ind) iCustom(NULL,TimeFrame,indicatorFileName,PERIOD_CURRENT,........., _buff,_ind)

3-

if (_Digits==5 || _Digits==3)
    double PP= _Point*10;
else
    double PP= _Point;

[KSforex]

And what is meaning of this code ?

string test = (((state & 1)== 1)?"DN":"UP");

what is different with this code 

string test = (((state)== 1)?"DN":"UP");

I dont understand this part  ->  & 1

This is the original  code:

//+------------------------------------------------------------------+ //| Expert initialization function                                   | //+------------------------------------------------------------------+ void OnInit()   { //--- enable CHART_EVENT_MOUSE_MOVE messages    ChartSetInteger(0,CHART_EVENT_MOUSE_MOVE,1);   } //+------------------------------------------------------------------+ //| MouseState                                                       | //+------------------------------------------------------------------+ string MouseState(uint state)   {    string res;    res+="\nML: "   +(((state& 1)== 1)?"DN":"UP");   // mouse left    res+="\nMR: "   +(((state& 2)== 2)?"DN":"UP");   // mouse right     res+="\nMM: "   +(((state&16)==16)?"DN":"UP");   // mouse middle    res+="\nMX: "   +(((state&32)==32)?"DN":"UP");   // mouse first X key    res+="\nMY: "   +(((state&64)==64)?"DN":"UP");   // mouse second X key    res+="\nSHIFT: "+(((state& 4)== 4)?"DN":"UP");   // shift key    res+="\nCTRL: " +(((state& 8)== 8)?"DN":"UP");   // control key    return(res);   } //+------------------------------------------------------------------+ //| ChartEvent function                                              | //+------------------------------------------------------------------+ void OnChartEvent(const int id,const long &lparam,const double &dparam,const string &sparam)   {    if(id==CHARTEVENT_MOUSE_MOVE)       Comment("POINT: ",(int)lparam,",",(int)dparam,"\n",MouseState((uint)sparam));   }

 I didn't find anything here Ternary Operator ?:

Thanks for help

[William Roeder]

KSforex: I dont understand this part  ->  & 1

string test = (((state & 1)== 1)?"DN":"UP"

I didn't find anything here Ternary Operator ?:

1. Take state, isolate the least significant bit (i.e. the value one,) see if it is set (i.e. is one.)
   
2. Read the manual again. If its odd, set test="DN", otherwise set test="UP"