Вылет программы при создании объекта

#ifndef MATRIX_H
#define MATRIX_H
 
#include <iostream>
 
typedef int Item;
 
class Matrix
{
private:
    int m_row;
    int m_col;
    Item ** matrix;
 
public:
    Matrix(int row, int col);
    explicit Matrix(int col);
    Matrix(const Matrix & m);
    ~Matrix();
 
    void reset();
    void fill_rand(int fromNum, int toNum);
    void fill_by_user();
    Item find_min_value();
    Item find_max_value();
    Item find_avg_value();
 
    Matrix & operator=(const Matrix & m);
    Matrix & operator*(const Matrix & m);
    friend std::ostream & operator<<(std::ostream & os, const Matrix & m);
};
 
#endif // MATRIX_H

#include "Matrix.h"
#include <ctime>
#include <cstdlib>
#include <windows.h>
 
Matrix::Matrix(int row, int col)
{
    m_row = row;
    m_col = col;
 
    matrix = new Item * [m_row];
    for (int i = 0; i < m_row; ++i)
        matrix[i] = new Item[m_col];
}
 
Matrix::Matrix(int col)
{
    m_row = 1;
    m_col = col;
 
    matrix = new Item * [m_row];
    for (int i = 0; i < m_row; ++i)
        matrix[i] = new Item[m_col];
}
 
Matrix::Matrix(const Matrix & m)
{
    m_row = m.m_row;
    m_col = m.m_col;
 
    matrix = new Item * [m_row];
    for (int i = 0; i < m_row; ++i)
        matrix[i] = new Item[m_col];
 
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            matrix[i][j] = m.matrix[i][j];
}
 
Matrix::~Matrix()
{
    for (int i = 0; i < m_row; ++i)
        delete [] matrix[i];
    delete [] matrix;
}
 
void Matrix::reset()
{
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            matrix[i][j] = 0;
}
 
void Matrix::fill_rand(int fromNum, int toNum)
{
    Sleep(800);
    srand(time(0));
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            matrix[i][j] = fromNum + rand()%(toNum - fromNum);
}
 
void Matrix::fill_by_user()
{
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
        {
            std::cout << "\nEnter a value of the element matrix["
                      << i <<"][" << j << "]: ";
            std::cin >> matrix[i][j];
        }
}
 
Item Matrix::find_min_value()
{
    Item min_value = matrix[0][0];
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            if (min_value > matrix[i][j])
                min_value = matrix[i][j];
    return min_value;
}
 
Item Matrix::find_max_value()
{
    Item max_value = matrix[0][0];
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            if (max_value < matrix[i][j])
                max_value = matrix[i][j];
    return max_value;
}
 
Item Matrix::find_avg_value()
{
    Item sum = 0;
    for (int i = 0; i < m_row; ++i)
        for (int j = 0; j < m_col; ++j)
            sum += matrix[i][j];
    return sum / (m_row * m_col);
}
 
Matrix & Matrix::operator=(const Matrix & m)
{
    if (this != &m)
    {
        for (int i = 0; i < m_row; ++i)
            delete [] matrix[i];
        delete [] matrix;
 
        m_row = m.m_row;
        m_col = m.m_col;
 
        matrix = new Item * [m_row];
        for (int i = 0; i < m_row; ++i)
            matrix[i] = new Item[m_col];
 
        for (int i = 0; i < m_row; ++i)
            for (int j = 0; j < m_col; ++j)
                matrix[i][j] = m.matrix[i][j];
    }
 
    return *this;
}
 
Matrix & Matrix::operator*(const Matrix & m)
{
    if (m_row == m.m_row && m_col == m.m_col)
    {
        for (int i = 0; i < m_row; ++i)
            for (int j = 0; j < m_col; ++j)
                matrix[i][j] *= m.matrix[i][j];
    }
 
    return *this;
}
 
std::ostream & operator<<(std::ostream & os, const Matrix & m)
{
    for (int i = 0; i < m.m_row; ++i)
    {
        for (int j = 0; j < m.m_col; ++j)
            os << m.matrix[i][j] << "\t";
        os << "\n";
    }
 
    return os;
}

#include "Matrix.h"
 
int main()
{
    std::cout << "Please choose number of rows: ";
    int rsize;
    std::cin >> rsize;
    std::cout << "Please choose number of columns: ";
    int csize;
    std::cin >> csize;
    Matrix matrix1(rsize, csize);
 
    matrix1.fill_by_user();
    std::cout << "\nThis is first matrix filled by user:\n"
              << matrix1;
 
    Matrix matrix2(rsize, csize);
    matrix2.fill_rand(10, 99);
    std::cout << "\nThis is second matrix filled by computer:\n"
              << matrix2;
 
    std::cout << "\nThis is the first matrix after multiplication by a second:\n"
              << matrix1 * matrix2;
 
    matrix1 = matrix2;
    std::cout << "\nThis is first matrix after assign to second matrix:\n"
              << matrix1;
 
    Matrix matrix3(csize);
    matrix3.fill_rand(10, 99);
    std::cout << "\nThis is third matrix:\n"
              << matrix3;
 
    return 0;
}