User defined array size

[daileycon]

input   int              SpreadsToCollect = 10;
double spreads[SpreadsToCollect];

 How do you do this? I get "invalid index value".

[Vladimir Karputov]

daileycon:

 How do you do this? I get "invalid index value".

You need to use a dynamic array, and then resize its size:

//+------------------------------------------------------------------+
//|                                                         Test.mq5 |
//|                              Copyright © 2016, Vladimir Karputov |
//|                                           http://wmua.ru/slesar/ |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2016, Vladimir Karputov"
#property link      "http://wmua.ru/slesar/"
#property version   "1.000"
#property script_show_inputs
//--- inputs
input int SpreadsToCollect=10;
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
   double spreads[];
   Print("ArraySize before: ",ArraySize(spreads));
   if(ArrayResize(spreads,SpreadsToCollect)==-1)
      Print("Error ArrayResize, #",GetLastError());
   else
      Print("ArraySize after: ",ArraySize(spreads));
  }
//+------------------------------------------------------------------+

Output:

2016.10.04 13:05:10.073 Test (EURUSD,M5)        ArraySize before: 0
2016.10.04 13:05:10.073 Test (EURUSD,M5)        ArraySize after: 10

[daileycon]

Karputov Vladimir:

You need to use a dynamic array, and then resize its size:

Output:

Weird, I thought I tried to resize it. I didn't have #property script_show_inputs

Thanks for the quick help!!! 

[Vladimir Karputov]

daileycon:

Weird, I thought I tried to resize it. I didn't have #property script_show_inputs

Thanks for the quick help!!! 

There are dynamic arrays (my example above) and static. An example of a static array:

   double spreads[10]; // a static array
   Print("ArraySize before: ",ArraySize(spreads));