CODEWITHSUNDEEP
c++
nickik
nickik

Reputation: 5881

C++ array of classes

I working on a game but I have a problem with the initialization of the level. (feld is just field in german)

class level{
private:
    feld spielfeld[10][10];
public:
/*
other stuff
*/
    void init_feld();
};

void level::init_feld()
{
    for(int i=0;i!=10;i++){
        for(int n=0;n!=10;n++){
            spielfeld[i][n] = new feld(land, i, n);
        }
    }
}

The Error:

Error: no match for »operator=« in »((level*)this)->level::spielfeld[i][n] = (operator new(24u), (, ((feld*))))« /home/nick/stratego/feld.h:18:11:

Remark: candidate is: feld& feld::operator=(const feld&) Process terminated with status 1 (0 minutes, 0 seconds) 2 errors, 0 warnings

Upvotes: 0

Views: 292

Answers (5)

TheJuice
TheJuice

Reputation: 4484

The other answers are correct in that you have a type mismatch in your use of the assignment operator. The error message can be explained as saying that the feld class has no assignment operator (operator=) that takes a pointer to a feld (feld *). The candidate function it is suggesting is likely the default assignment operator (unless you have implemented your own operator=).

So as the other answers suggest, you could change the type of the spielfeld to take pointers to feld objects or you could remove the use of operator new when you assign the felds to the array (of course this would then allocate them on the stack, which you may not want if they are large in size).

Upvotes: 0

Roddy
Roddy

Reputation: 68023

You're using "new", but feld isn't an array of pointers, it's an array of objects.

Two choices -

  • Make it an array of pointers. feld * spielfeld[10][10] Beware that if you do this, you've now got to worry about deleting the objects which are created by 'new'.

  • Or, leave it as an array of objects (no wories about 'delete#) and initialize them differently.

spielfeld[i][n] = feld(land, i, n); // uses assignment operator

This isn't the most efficient or elegant way as intermediate feld items get constructed and deleted, but it should work. Depending on what values feld contains you might need to write an assignment operator....

Upvotes: 0

Jasmeet
Jasmeet

Reputation: 2352

The = operator defined in feld wants a (const) reference to feld and you are passing it a pointer to feld

Upvotes: 0

CB Bailey
CB Bailey

Reputation: 791361

spielfeld[i][n] is a feld object, new feld(land, i, n) dynamically allocates a new feld object and returns a pointer to that object. If you want to assign to a feld value to spielfeld[i][n] you could use:

spielfeld[i][n] = feld(land, i, n);

Alternatively you may be able to set the appropriate members of spielfeld[i][n] directly or using other member functions.

Upvotes: 6

Didier Trosset
Didier Trosset

Reputation: 37427

You need to declare an array of array of pointers to feld.

class level{
private:
    feld * spielfeld[10][10];   // <-- Added pointer to here
public:
/*
other staff
*/
    void init_feld();
};

Upvotes: 1

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