Please, provide more code. You have some errors in omitted part. This compiles:
class CQ; // forward declaration class CI //: public CObject { public: CI(CQ* &q[], const int id); // contructor }; class CQ { public: CQ(int i){}; }; CI::CI(CQ* &q[], const int id) { int i = 0; int n = ArraySize(q); // start to create another (new) instance of CQ ArrayResize(q,n+1); // one more q[n] = new CQ(i); // NO ERROR HERE }
Please, provide more code. You have some errors in omitted part. This compiles:
May be it does not compiler here with me because CQ is one file and CI the other file?
// file CI.mqh class CQ; // forward declaration class CI //: public CObject { public: CI(CQ* &q[], const int id); // contructor }; CI::CI(CQ* &q[], const int id) { int i = 0; int n = ArraySize(q); // start to create another (new) instance of CQ ArrayResize(q,n+1); // one more q[n] = new CQ(i); // and now?? }This part was from the other file it is not part of the file for the class CI!!
//file CQ.mqh class CQ { public: CQ(int i){}; };
May be it does not compiler here with me because CQ is one file and CI the other file?
This part was from the other file it is not part of the file for the class CI!!Anyway try this - it's the complete file:
//+------------------------------------------------------------------+ //| CI.mqh | //| Test | //| http://www.mql5.com | //+------------------------------------------------------------------+ #property copyright "Test" #property link "http://www.mql5.com" #property version "1.00" #property strict //+------------------------------------------------------------------+ //| | //+------------------------------------------------------------------+ class CQ; class CI { private: public: CI(CQ* &q[], const int id); // contructor ~CI(); }; //+------------------------------------------------------------------+ //| | //+------------------------------------------------------------------+ CI::CI(CQ* &q[], const int id) { int n = ArraySize(q); // start to create another (new) instance of CQ ArrayResize(q,n+1); // one more q[n] = new CQ(id); // and now?? } //+------------------------------------------------------------------+ //| | //+------------------------------------------------------------------+ CI::~CI() { } //+------------------------------------------------------------------+
Anyway try this - it's the complete file:
I can't include it as CQ has as well a forward declaration to CI.
As it is not possible for both files to include each other I have to use the forward declaration.
I can't include it as CQ has as well a forward declaration to CI.
As it is not possible for both files to include each other I have to use the forward declaration.
class CQ; // forward declaration class CI { public: CI(CQ* &q[], const int id); // contructor }; class CQ { private: const CI *owner; public: CQ(const CI *o) { owner = o; }; }; CI::CI(CQ* &q[], const int id) { int n = ArraySize(q); // start to create another (new) instance of CQ ArrayResize(q,n+1); // one more q[n] = new CQ(&this); }Both classes have references to each other. No problem.
ok - thanks!
But I thought it would be a nice feature of OOP to have each class with its library of methods in its own file.
ok - thanks!
But I thought it would be a nice feature of OOP to have each class with its library of methods in its own file.
Sure, it is quite common, in fact Java has it as the mandatory rule for public classes. Though the circular dependencies in your example are not a good example of a public class.
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in the class CI the constructor needs to create an instance of another class (CQ) which is forward declared - but this fails :(
The mt4 compiler complains:
Cry - why?
The constructor of CQ exists with exactly this parameter (in case the compiler checks the existence of CQ...), but anyway the class CQ is declared (forward) in IC - what do I wrong??
Thanks!