Re: ctor, operator =

From: marbac (marbac_at_chello.at)
Date: 03/19/05 

Date: Sat, 19 Mar 2005 11:10:27 GMT

Andrey Tarasevich schrieb:

> In general case - no. Assignment operator is normally applied to the
> already constructed object and in general case the implementation of the
> assignment operator will rely on that fact. In the code above you are
> trying to apply the assignment operator to an object, which has not been
> constructed yet. Whether this is a problem in your particular case
> depends on your class implementation details.

Well i reduced my code to a simple example to show my problem.
And I also found the mistake i made ... what a mess, because
it has nothing to do with the question "
copy constructor with operator = is valid?"

thanks a lot and regards marbac

#include <iostream>

class test {

public:
        test (int _size): size(_size) {
                if (size>0) array=new int [this->size];
                        else array=0;
                
        }
        
        test (test& src) {
                array=0; // THIS WAS MISSING!!
                *this=src;
        }
        
        ~test () {
                if (array) delete [] array;
        }
        
        test& operator = (const test& src) {
                size=src.size;
                if (array) delete [] array;
                if (size>0) array=new int [this->size];
                        else array=0;
                return *this;
        }
        
        void cout_size () {
                std::cout << "Size:" << size << std::endl;
        }
                
private:
        int *array;
        int size;
};

int main () {
        test a(4);
        test b(5);
        test c(6);
        
        a.cout_size();
        b.cout_size();
        c.cout_size();
        
        a=b;
        a.cout_size();
        
        test d (a); //runtime - error if deleting non 0 pointer at construction
time
        d.cout_size ();
}

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