Двумерные динамические массивы. Удаление заданных колонок.

#include <iostream>
#include <iomanip>
#include <string>
#include <ctime>

using namespace std;

bool __cdecl random_matrix(int **, const size_t, const size_t, const int _left = -5, int _rigth = 51);
void __cdecl show_matrix(int **, const size_t, const size_t);
bool __cdecl is_positive_column(int **, const size_t, const size_t);
void __cdecl delete_column(int **, int **, const size_t, const size_t, const size_t);
void __cdecl copy_matrix(int **, int **, const size_t, const size_t);
void __cdecl delete_matrix(int **, size_t);
int ** __cdecl create_matrix(int **, const size_t, const size_t);

int main() {
    srand(unsigned(time(NULL)));
    wcout.imbue(locale("rus_rus.866"));

    wcout << L"Введите строки: ";
    size_t rows;
    cin >> rows;
    wcout << L"Введите столбцы: ";
    size_t cols;
    cin >> cols;

    int ** matrix = NULL;
    matrix = create_matrix(matrix, rows, cols);

    if (random_matrix(matrix, rows, cols)) {
        wcout << L"Исходная матрица:\n";
        show_matrix(matrix, rows, cols);

        for (size_t index = 0; index < cols; index++)
            if (is_positive_column(matrix, rows, index)) {
                int ** temp = NULL;
                temp = create_matrix(temp, rows, cols);
                copy_matrix(temp, matrix, rows, cols);
                delete_matrix(matrix, rows);
                size_t new_cols = cols - 1;
                matrix = create_matrix(matrix, rows, new_cols);
                delete_column(matrix, temp, rows, cols, index);
                --cols;
                --index;
                delete_matrix(temp, rows);
                temp = NULL;
            }

        wcout << L"Изменённая матрица:\n";
        show_matrix(matrix, rows, cols);
    } else wcout << L"\aНе удалось заполнить матрицу!\n";

    delete_matrix(matrix, rows);
    matrix = NULL;

    cin.get(); cin.get();
}

inline bool random_matrix(int ** _matrix, const size_t _rows, const size_t _cols, const int _left, int _rigth) {
    if (_left >= _rigth) return false;

    if (_left < 0 && _rigth >= 0) _rigth += abs(_left);
    else if (_left < 0 && _rigth < 0) _rigth = abs(_left) - abs(_rigth);
    else if (_left >= 0 && _rigth > 0) _rigth -= _left;

    for (size_t row = 0; row < _rows; row++)
        for (size_t col = 0; col < _cols; col++)
            _matrix[row][col] = rand() % _rigth + _left;

    return true;
}

void show_matrix(int ** _matrix, const size_t _rows, const size_t _cols) {
    if (_cols && _rows)
        for (size_t row = 0; row < _rows; row++, cout << endl)
            for (size_t col = 0; col < _cols; col++)
                cout << setw(5) << _matrix[row][col];
    else wcout << L"Нет данных для отображения!\n";
}

bool is_positive_column(int ** _matrix, const size_t _rows, const size_t _col_index) {
    for (size_t row = 0; row < _rows; row++)
        if (_matrix[row][_col_index] < 0)
            return false;
    return true;
}

void delete_column(int ** _matrix, int ** _temp, const size_t _rows, const size_t _cols, const size_t _col_index_del) {
    size_t next;

    for (size_t row = 0; row < _rows; row++) {
        next = 0;

        for (size_t col = 0; col < _cols; col++)
            if (col != _col_index_del)
                _matrix[row][next++] = _temp[row][col];
    }
}

void copy_matrix(int ** _in_matrix, int ** _from_matrix, const size_t _rows, const size_t _cols) {
    for (size_t row = 0; row < _rows; row++)
        for (size_t col = 0; col < _cols; col++)
            _in_matrix[row][col] = _from_matrix[row][col];
}

void delete_matrix(int ** _matrix, size_t _rows) {
    for (size_t row = 0; row < _rows; row++)
        delete[] _matrix[row];
    delete[] _matrix;
}

int ** create_matrix(int ** _matrix, const size_t _rows, const size_t _cols) {
    _matrix = new int * [_rows];

    for (size_t row = 0; row < _rows; row++)
        _matrix[row] = new int [_cols];

    return _matrix;
}