Thread: how to find where the memory is freed ?

Hello..

i learn math and C++ and i thouth to combine both to make my life easeir:
i wrote a simple class that by using it i will be able to calculate relation matrix in the power n.

my problem is that in unable to store the object (it getting freed) and i can't store it.
the function bool_mutilpication need to return a object and store it inside a new one.
matrix_c = matrix_a * matrix_b

im able to do (object * object).Print();
but not object = other_object * more_other_object ; //dobule free.

Code:

/***************************************************************************
 *            matrics.cc
 *
 *  Fri Jun  1 09:23:55 2007
 *    Jabka Atu
 *  Email mashrom{d0t}[email protected]
 ****************************************************************************/

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 
#include <iostream>
#include <assert.h>

using namespace std;

bool** multiply(const bool **matA,int rows,int colmuns,int colmuns_of_sec_matrix, const bool **matB);

class bool_matrix{
	 int rows;
	 int colmuns;
	 
	 bool** matrix;
	 
	 void init();
	 public:
		
	 	bool** _matrix;
		int size;	
	 	bool_matrix();
	 	~bool_matrix();
	 	bool_matrix(int m,int n);
	 	bool_matrix(const bool_matrix &other);
		void Print(); 
	 	bool_matrix boolean_multiply(const  bool_matrix &other);
		bool& set_values(int rows,int colmuns);
	 	bool_matrix operator * (const bool_matrix& other){
			bool_matrix result(this->boolean_multiply(other));
			return result;
		}
		bool_matrix& operator= (const bool_matrix &other);		
 };


bool_matrix& bool_matrix::operator= (const bool_matrix &other){
	size = other.size;
	rows = other.rows;
	colmuns = other.colmuns;
	matrix = other.matrix;
	return *this;

}
void bool_matrix::init(){
	matrix = new bool* [rows];
	assert(matrix);
	for (int i = 0;i < rows ; i++) 	 
	{
		matrix[i] = new bool [colmuns];
		assert(matrix[i]);
	}
	/*
	can be done by .. 
	for (int i = 0;i  < rows;i++)
		for (int j=0;j < colmuns;j++)
			matrix[i][j]=false;
   */
	
	for (int i=0 ; i < rows * (colmuns - 1); i++)
		*(*matrix + i) = false;
	
	_matrix = matrix;
	 
}
 bool_matrix::bool_matrix() {
	 rows = 0;
	 colmuns = 0;
	 size = 0;
	 init();
	 
 }
 bool_matrix::~bool_matrix(){
	 if (!matrix) //check if there is actually allocated memory
	 {
		 for (int i = 0;i < rows;i++)
			 delete [] matrix[i];
	 }
	 delete [] matrix;
	 
 }

 bool_matrix::bool_matrix(int m,int n){
	 rows    = m;
	 colmuns = n;
	 size    = m * n;
	 init();
	
}

bool_matrix::bool_matrix(const bool_matrix &other){
	this -> rows    = other.rows;
	this -> colmuns = other.colmuns;
	this -> size 	= other.size;
	
	init();
	for (int i = 0;i < rows;i++)
		for (int j = 0;j < colmuns;j++)
				this->matrix[i][j] = other.matrix[i][j]; 
	
}

void bool_matrix::Print(){

	for (int i=0;i<rows;i++)
	{
		for(int j = 0; j< colmuns;j++)
			cout<<matrix[i][j];
		cout<<endl;
	}
	
}

bool_matrix  bool_matrix::boolean_multiply(const  bool_matrix &other){
	
	bool_matrix result((*this).rows ,other.colmuns);
	bool **returned_matrix = NULL;
	returned_matrix =  multiply((const bool**) (*this).matrix,(*this).rows,(*this).colmuns,other.colmuns,(const bool**) other.matrix);
	result.matrix = returned_matrix;
	return result;
}

bool& bool_matrix::set_values(int rows,int colmuns){
	return matrix[rows][colmuns];
}

bool** multiply(const bool **matA,int rows,int colmuns,int colmuns_of_sec_matrix, const bool **matB){
	
	
	bool **matrix;
	//create a new matrix for result
	matrix = new bool* [rows];
	assert(matrix);
	
	for (int i = 0;i < rows; i++)
		matrix[i] = new bool [colmuns_of_sec_matrix];
	assert(matrix);
	//End of creation of matrix.
	
	//intlize matrix
	for (int i = 0;i < rows ; i++)
		for (int j = 0 ; j < colmuns_of_sec_matrix ; j++)
			matrix[i][j]= false;
	//End initlization
		
	for (int i=0;i < rows ; i++)
	{
		for (int j=0 ;j < colmuns ; j++)
			for (int k=0 ; k<colmuns_of_sec_matrix ; k++)
			{
				if ((matA[i][j] == matB[j][k]) and (matA[i][j] == 1))
				{
				
					matrix[i][k] = true;
					continue; //if even one pair (a)ij = (b)jk = 1 then (a)ik will be 1.so no need to go to check for more
				}
			
			}
		
	}
		return matrix;
}

int main(){
    
	bool_matrix a(4,3),b(3,4),c;
	
	a._matrix[0][0]=1;
	a._matrix[0][1]=1;
	a._matrix[0][2]=0;
	a._matrix[1][0]=0;
	a._matrix[1][1]=1;
	a._matrix[1][2]=0;
	a._matrix[2][0]=1;
	a._matrix[2][1]=1;
	a._matrix[2][2]=0;
	a._matrix[3][0]=0;
	a._matrix[3][1]=0;
	a._matrix[3][2]=1;
	
	b._matrix[0][0]=1;
	b._matrix[0][1]=0;
	b._matrix[0][2]=0;
	b._matrix[0][3]=0;
	b._matrix[1][0]=0;
	b._matrix[1][1]=1;
	b._matrix[1][2]=1;
	b._matrix[1][3]=0;
	b._matrix[2][0]=1;
	b._matrix[2][1]=0;
	b._matrix[2][2]=1;
	b._matrix[2][3]=1;
	
	c = a * b; //dobule freea 
	
	return 0;
 }

and why do you want to free a and b? they are statically created and continue to exists after your operator usage...

about the copy:
i though since allready i allocated memory for one i could use it;//why waste memory

it is for math studies" discrete mathematical structures" (sounds terrfing but actualy pretty easy and helpfull).

we need to find if some relations are transitive symmetric and reflexive and to calculate Matrix^n
and since it is hard work (try to calculate matrix of power 6 when dealing 10 on 10 matrix).

since i study cpp i guessed i could kill to birds with one stone ..

anyway ..

i changed to this :

Code:

bool_matrix& bool_matrix::operator= (const bool_matrix &other){
	
	
	size = other.size;
	rows = other.rows;
	colmuns = other.colmuns;
	
	//matrix = other.matrix;
	init();
	for (int i = 0;i < rows;i++)
		for (int j = 0;j < colmuns;j++)
				this->matrix[i][j] = other.matrix[i][j]; 
	
	return *this;

}

also changed the destructer to :

Code:

bool_matrix::~bool_matrix(){
	 if (matrix != NULL) //check if there is actually allocated memory
	 {
		 for (int i = 0;i < rows;i++)
			 delete [] matrix[i];
	 
	 delete [] matrix;
	 }
 }

and
in check in bool_multiplication for rows = columns :

Code:

bool_matrix  bool_matrix::boolean_multiply(const  bool_matrix &other){
	
	bool_matrix result((*this).rows ,other.colmuns);
	bool **returned_matrix = NULL;
	if ((this->colmuns) != (other.rows))
	{
		cout<<"undefined multiplication colmuns of first matrix isn't equal rows\n";
	}
	else
	{
			returned_matrix =  multiply((const bool**) (*this).matrix,(*this).rows,(*this).colmuns,other.colmuns,(const bool**) other.matrix);
			result.matrix = returned_matrix;
	}
	return result;
}

it's alive ...

now being a little bit serious;
why did that object had been deleted if transfers it adders since the original memory was allocated using new did it mean that i have memory leakage ?

also:
i need to somehow implement initialising it with strings and creating an array as in the length of each string :
bool_matrix(char *str);
bool_matrix(char *str,char *str);
but how can i do it for unknown size ?

how can implement the foo objname[]={0,0,0,0,.... };

p.s.
time for me to learn how to use vectors..

time for me to learn how to use vectors..

Here ya go: http://www.codeguru.com/cpp/cpp/cpp_...cle.php/c4027/

Also time for you to learn how to spell..
Here's a translation table for others to interpret your post:

thouth -> thought (what you wrote rhymes with mouth!)
structers -> structures
semtric -> symmetric
rflexive -> reflexive
distructer -> destructor
sireus -> serious
initlizing -> initialising
unkown -> unknown
preety -> pretty

oh and 'somehow' should have been one word where you used 'some how'.

> initialising
Debatable.
http://www.google.ca/search?q=initialising
http://www.thefreedictionary.com/initialising