How to add a Sort method to my wxArray Topic is solved

[posta10100]

Hello!
I need to add a Sort method to my derived wxArray class.

I see that the header of method is

void Sort(CMPFUNC<T> compareFunction)

I need to add in my class something that accept a method (written in another class) like this:

Code: Select all

int wxCMPFUNC_CONV AClass::sortSegments(MySegment *s, MySegment *s1) {
    if (...) {
        return 0;
    }
    if (...) {
        return 1;
    }
    return -1;
}

and call the sort method of the wxArray class.

Someone can help me?

Thanks!!!

[lowjoel]

Yes, your function is perfectly fine and legal. You may have problems with the this pointer however, since the sort function does not allow you to provide one when the object method is used from a pointer. You should change your sorting function to be a static member function if you want to use this approach, or you can use a global function.

Then, just call myArray.Sort(&AClass::sortSegments); if you are using a static member function, or myArray.Sort(sortSegments) if you are using a global function.

Joel

[posta10100]

What are you saying is that in the AClass class I have to declare a static method

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static int wxCMPFUNC_CONV AClass::sortSegments(MySegment *s, MySegment *s1);

and then I have to call the sort method in the myArray class declared as

Code: Select all

void Sort(CMPFUNC compareFunction);

with the command

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myArray *arr = new myArray();
arr->Add(...);
arr->Add(...);
arr->Add(...);
arr->Sort(&AClass::sortSegments);

Is it correct?

Thanks for your help!

[lowjoel]

Yep. Do you have problems using that?

Joel

[posta10100]

Yes, it don't work...

In myArray header file I put:

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WX_DECLARE_OBJARRAY(MySegment*, MySegmentArray);
...
void Sort(CMPFUNC compareFunction);
...
MySegmentArray *m_SegmentArray;

while in the cpp there is:

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void myArray::Sort(CMPFUNC compareFunction) {
    m_SegmentArray->Sort(compareFunction); //This is the line 70
}

But when I try to compile I have this error:

70 Z:\Luca\myArray.cpp invalid conversion from `int (*)(const void*, const void*)' to `int (*)(MySegment***, MySegment***)'

Again, thanks for your help!!!

Luca.

[lowjoel]

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typedef int (*SegmentSortFunc)(MySegment***, MySegment***);
m_SegmentArray->Sort(reinterpret_cast<SegmentSortFunc>(compareFunction));

Hope that works (I use the STL so I don't have to use these weird sorting functions)

Joel

[DavidHart]

Hi,

This works for me.

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WX_DECLARE_OBJARRAY(class Foo, FooArray);

...

static int wxCMPFUNC_CONV StringCompareFunction(Foo **first, Foo **second)
{
return (*first)->GetString().CmpNoCase((*second)->GetString());
}

static int wxCMPFUNC_CONV IntCompareFunction(Foo **first, Foo **second)
{
return (*first)->Int > (*second)->Int;
}

// Usage:

FooArray array;
...
array.Sort( StringCompareFunction );  // Sort by string
// array.Sort( IntCompareFunction ); or by Int

Note that my wxArray is of objects, while yours is of pointers to objects (btw, is that allowed in WX_DECLARE_OBJARRAY? If you want pointers, why not use WX_DEFINE_ARRAY?)

Hope this helps.

Regards,

David

[posta10100]

Code: Select all

typedef int (*SegmentSortFunc)(MySegment***, MySegment***);
m_SegmentArray->Sort(reinterpret_cast<SegmentSortFunc>(compareFunction));

Hope that works (I use the STL so I don't have to use these weird sorting functions)

Joel

This works with a little modification:

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static int wxCMPFUNC_CONV AClass::sortSegments(void *s, void *s1);

In this way it works!!

Thanks!!!!!