array questions

[faustf]

hi guys  , why if i decleare array in this mode return me error invalid index value ?

int VisibleBar=WindowFirstVisibleBar();

double aBodyCount[VisibleBar];

is a integer

[Drazen Penic]

If you want static array - one with a size defined at declaration time - you must use constant to declare size.

If you want variable sized array, read about dynamic arrays and ArrayResize() function.

[faustf]

I i want static array , and i suppsoe

int VisibleBar=WindowFirstVisibleBar()

retrun a integer value , why give me error

[Keith Watford]

Comments that do not relate to this topic, have been moved to "Off Topic Posts".

[Drazen Penic]

faustf:
I i want static array , and i suppsoe

retrun a integer value , why give me error

As I already wrote:

you must use constant to declare size

In your code "VisibleBar" is a variable, not a constant.

[Keith Watford]

faustf:
I i want static array , and i suppsoe

retrun a integer value , why give me error

Drazen Penic:

If you want static array - one with a size defined at declaration time - you must use constant to declare size.

If you want variable sized array, read about dynamic arrays and ArrayResize() function.

[faustf]

but now  why tell  me out of range  ?? whats wrong ?

#property indicator_chart_window
extern int    font_size = 10;
extern color  ColorBull = DodgerBlue;
extern color  ColorBeer = Red;
extern string font_name = "Arial";
double aBodyCount[2];
//+------------------------------------------------------------------+
int start()
  {
  int VisibleBar=WindowFirstVisibleBar();
    ArrayResize(aBodyCount,VisibleBar,VisibleBar);
   BodyCount();  
  }
//+------------------------------------------------------------------+
int deinit()
  {
   ObjectsDeleteAll(0,OBJ_TEXT);
   return(0);
  }
//+------------------------------------------------------------------+

//+------------------------------------------------------------------+
//|            BODY COUNT VISIBLE                                    |
//+------------------------------------------------------------------+
void BodyCount()
  {
   for(int i=WindowFirstVisibleBar(); i>=0; i--)
     {
      aBodyCount[i] = ((NormalizeDouble(Open[i],Digits)/Point)-(NormalizeDouble(Close[i],Digits))/Point);
     }
   Alert("Plus ", aBodyCount[i]," pt.");
   return ;
  }
//+------------------------------------------------------------------+

[William Roeder]

faustf: but now  why tell  me out of range  ?? whats wrong ?

1. Your array has two elements. WindowFirstVisibleBar is likely in the hundreds.
   
2. Next time: Use the debugger or print out your variables, including _LastError and prices and find out why. Do you really expect us to debug your code for you?

[Drazen Penic]

faustf:

but now  why tell  me out of range  ?? whats wrong ?

Array index is zero based, so if you have  WindowFirstVisibleBar() elements in your array, they have indexes from array[0] to array[WindowFirstVisibleBar()-1]

Your loop from the above snippet should start from WindowFirstVisibleBar()-1

And another thing to check is if WindowFirstVisibleBar() changes value as time passes. For example can it happen that on start WindowFirstVisibleBar() returns value 100, and after some time some bigger number? 
If that is the case, you will initialize array for 100 elements, and later you will expect it to have more.

You should get familiar how the arrays work in MQL and C++, otherwise you will have number of problems.

[faustf]

Drazen Penic:

Array index is zero based, so if you have  WindowFirstVisibleBar() elements in your array, they have indexes from array[0] to array[WindowFirstVisibleBar()-1]

Your loop from the above snippet should start from WindowFirstVisibleBar()-1

And another thing to check is if WindowFirstVisibleBar() changes value as time passes. For example can it happen that on start WindowFirstVisibleBar() returns value 100, and after some time some bigger number? 
If that is the case, you will initialize array for 100 elements, and later you will expect it to have more.

You should get familiar how the arrays work in MQL and C++, otherwise you will have number of problems.

yea  i understund  what you tell but , my case is different i know that  array start the count 0 to end  and i  if i create Array [2] ,resize it,  and  with(WindowFirstVisibleBar() + 5)and  cicle for insert inside of array  with  for(int i=WindowFirstVisibleBar(); i>=0; i--) , i aspect the script runn good , but return the same2020.05.15 23:19:13.116    candle-body-size USDCHF,H1: array out of range in 'candle-body-size.mq4' (60,29)
example if WindowFirstVisibleBar() is  equal = 100  and i resize in 105 , if  for start  to 0 or 1   for me is no problem i have 5 position plus

[lippmaje]

faustf:

yea  i understund  what you tell but , my case is different i know that  array start the count 0 to end  and i  if i create Array [2] ,resize it,  and  with(WindowFirstVisibleBar() + 5)and  cicle for insert inside of array  with  for(int i=WindowFirstVisibleBar(); i>=0; i--) , i aspect the script runn good , but return the same2020.05.15 23:19:13.116    candle-body-size USDCHF,H1: array out of range in 'candle-body-size.mq4' (60,29)
example if WindowFirstVisibleBar() is  equal = 100  and i resize in 105 , if  for start  to 0 or 1   for me is no problem i have 5 position plus

You cannot resize an array that was created static. You can only resize a dynamic array. ArrayResize() has a return value, check it to detect errors.