CODEWITHSUNDEEP
mql5
trader
trader

Reputation: 13

MQL5 iterate over struct

Is it possible to iterate over both dimensions of a struct? Being more specific, I was wondering wheather it is possible to iterate over the columns of a struct such as:

struct Struct { string NAME; int WERT; double VALUE; datetime TIME; int INT; string TYPE; };

Struct s[];

string cols[]={"NAME","WERT","VALUE","TIME","INT","TYPE" };

s[0].NAME = "B";
s[0].WERT = 10;
s[0].VALUE= 50.00;
s[0].TIME = TimeCurrent();
s[0].INT=5;
s[0].TYPE="Man";

s[1].NAME = "A";
s[1].WERT = 10000;
s[1].VALUE= 40000.00;
s[1].TIME = TimeCurrent();
s[1].INT=100;
s[1].TYPE="female";

for(int i=0; i<3; i++)
  {
   for(int j=0; j<=ArraySize(cols); j++)
     {
      s[i].cols[j]; // <-------------------
     }
  }

Upvotes: 0

Views: 600

Answers (2)

nicholishen
nicholishen

Reputation: 3012

You can actually use the JAson library for this type of behavior. linky

Example:

#include <jason.mqh>

void OnStart()
{
   CJAVal s;
   s[0]["NAME"] = "B";
   s[0]["WERT"] = 10;
   s[0]["VALUE"]= 50.00;
   s[0]["TIME"] = (int)TimeCurrent();
   s[0]["INT"]=5;
   s[0]["TYPE"]="Man";

   s[1]["NAME"] = "A";
   s[1]["WERT"] = 10000;
   s[1]["VALUE"]= 40000.00;
   s[1]["TIME"] = (int)TimeCurrent();
   s[1]["INT"]=100;
   s[1]["TYPE"]="female";

   Print(s.Serialize());
   for(int i=0; i<s.Size(); i++) {
      for(int j=0; j<s[i].Size(); j++) {
         string key = s[i].m_e[j].m_key;
         printf("%s = string(%s), int(%d), double(%.3f)", 
            key, 
            s[i][key].ToStr(),
            s[i][key].ToInt(),
            s[i][key].ToDbl()
         );
      }
   }
}

Although, you're much better off creating a to_string method on your structs and classes

struct Struct { 
   string   name; 
   int      wert; 
   double   value; 
   string   str() {
      return StringFormat("Struct(%s, %d, %.2f)", name, wert, value);
   }
};

Upvotes: 0

Daniel Kniaz
Daniel Kniaz

Reputation: 4691

Welcome to SOF!
First of all, it is better to avoid using complex structures such as string's inside the struct. Use class'es if you want your structures to have string values. Use an char[] and convert if you really need a string in it.
Second, You cannot know how much elements you have inside a struct and cannot iterate over that - no refrection, sorry. If I were you, I would convert your TYPE to bool (enum in case "male" and "female" is not enough :) and have an array of long's (including int, bool, datetime and any other integer types) and double's (add float's in it) then iterate over size of those two array's.

Upvotes: 0

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