ООП лаб 7(1)

#include <iostream>

using namespace std;

class matrix {
    private:
        int size_line,
            size_column,
            **p_matrix;
    public:
        matrix() {
            size_line = 0;
            size_column = 0;
            p_matrix = NULL;
        }
        matrix(int _size_line, int _size_column) {
            size_line = _size_line;
            size_column = _size_column;
            p_matrix = new int* [size_line];
            for (int i_line = 0; i_line < size_line; i_line++) {
                p_matrix[i_line] = new int[size_column];
                for (int i_column = 0; i_column < size_column; i_column++)
                    p_matrix[i_line][i_column] = 0;
            }
        }
        void input() {
            cout << "Enter size of line: ";
            cin >> size_line;
            cout << "Enter size of column: ";
            cin >> size_column;
            cout << "Enter elements your matrix: " << endl;
            p_matrix = new int* [size_line];
            for (int i_line = 0; i_line < size_line; i_line++) {
                p_matrix[i_line] = new int[size_column];
                for (int i_column = 0; i_column < size_column; i_column++)
                    cin >> p_matrix[i_line][i_column];
            }
        }
        void print() {
            if (p_matrix == NULL) {
                cout << "ERROR: empty matrix." << endl;
                return;
            }

            for (int i_line = 0; i_line < size_line; i_line++) {
                for (int i_column = 0; i_column < size_column; i_column++)
                    cout << p_matrix[i_line][i_column] << '\t';
                cout << endl;
            }
        }
        matrix operator* (const matrix &B) {
            if (size_column != B.size_line) {
                matrix ERROR;
                cout << "ERROR: unsuitable matrices." << endl;
                return ERROR;
            }

            matrix result(size_line, B.size_column);
            for (int i_fixed_line = 0; i_fixed_line < size_line; i_fixed_line++)
                for (int i_fixed_col = 0; i_fixed_col < B.size_column; i_fixed_col++)
                    for (int i_dynamic = 0; i_dynamic < size_column; i_dynamic++)
                        result.p_matrix[i_fixed_line][i_fixed_col] += p_matrix[i_fixed_line][i_dynamic] * B.p_matrix[i_dynamic][i_fixed_col];
            return result;
        }
};

int main() {
    matrix A;
    cout << "Enter matrix A: " << endl;
    A.input();
    matrix B;
    cout << "Enter matrix B: " << endl;
    B.input();

    cout << "Result A * B: " << endl;
    matrix C;
    C = A * B;
    C.print();

    return 0;
}