how to delay destructor call

vihrao (4)
I am using operator to add two matrices stored inside matrix objects. I instantiate and initialize two matrices. Then I call operator to add them. But before adding the two matrices: m1 and m2 , their destructors gets called. When I start adding the matrices, since m2 matrix array has been deleted, it crashes. How can I force the destructors to get called after I add the two matrices together.


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C++ Syntax (Toggle Plain Text)
// calling matrix initialization and additionm1.initMatrix();m1.print();m2.initMatrix();m2.print();rslt = m1-m2; //operatormatrix matrix::operator +(matrix m1){         matrix rslt = getResultMatrix(rows, cols, 0);  	for(int n=0; n<iterations; n++)	{		for(int i=0; i<rows; i++)   		{   			for(int j=0; j<cols; j++)      			{         			rslt.m[i][j] = this->m[i][j]+m1.m[i][j];       			}    		}	} 	return rslt; }// destructormatrix::~matrix(){ 	delete[] this->m;}// calling matrix initialization and addition
m1.initMatrix();
m1.print();
m2.initMatrix();
m2.print();
rslt = m1-m2;

//operator
matrix matrix::operator +(matrix m1)
{
	
        matrix rslt = getResultMatrix(rows, cols, 0); 

	for(int n=0; n<iterations; n++)
	{
		for(int i=0; i<rows; i++)
   		{
   			for(int j=0; j<cols; j++)
      			{
         			rslt.m[i][j] = this->m[i][j]+m1.m[i][j];
				
      			}

   		}
	}
	
	return rslt;

}
// destructor
matrix::~matrix()
{
		
	delete[] this->m;
}
PanGalactic (1658)
1. Pass the matrix m1 as a const reference on line 10.
2. Classes with pointers require you to define a copy constructor, assignment operator and destructor. You have only provided one of those.

PanGalactic (1658)
OK, that was a rather terse reply. Apologies.

Because you do not define a copy constructor and assignment operator, when you pass the argument on line 10 by value, a copy is made. That copy is just a copy of the pointer this->m, and not the memory pointed by this->m. When that temporary copy is destroyed, the memory is deleted by the destructor. But you still have another object pointing to the same piece of memory.
vihrao (4)
My mistake. After debugging I found that the destructor is being called on result matrix just after the line:
matrix rslt = getResultMatrix(rows, cols, 0);
Destructor is not called on on m1 as I thought so.

I am instantiating a matrix object inside getResultMatrix like this:
matrix r;
then I populate 'r' and retun 'r' .
But when I look at the returned objectr 'rslt' just after getResultMatrix exection, I see nulls inside it. This may be the reason. How to fix this?
PanGalactic (1658)
2. Classes with pointers require you to define a copy constructor, assignment operator and destructor.


Have you defined a copy constructor and an assignment operator for the matrix class yet? If so, what do they look like?
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