2. Ввод матрицы 3х3 и подсчет определителя.

#include <iostream>
int main() {
    double matrix[3][3], fs[3], dsm[3][2][2], pdet[3], det[3], determinant; int i, j, m, l; char a;
    for (i = 0; i < 3; i++) {
        for (j = 0; j < 3; j++) {
            std::cout << "Enter " << i + 1 << "," << j + 1 << " element of matrix: ";
            std::cin >> matrix[i][j];
        }
    }
    std::cout << "Do you matrix look like:" << std::endl;
    do {
        for (i = 0; i<3; i++) {
            for (j = 0; j < 3; j++) {
                std::cout << matrix[i][j] << " ";
            }
            std::cout << std::endl;
        }
        std::cout << "You should enter answer (y/n): ";
        std::cin >> a;
        if (a != 'y' && a != 'n') {
            std::cout << "You didn't answer" << std::endl;
        }
        else if (a == 'n') {
            std::cout << "What element is incorrect?" << std::endl;
            do {
                std::cout << "Please enter string number: ";
                std::cin >> i;
                if (i > 3 || i < 1) {
                    std::cout << "Error. Incorrect number. Try again." << std::endl;
                }
            } while (i > 3 || i < 1);
            i = i - 1;
            do {
                std::cout << "Please enter column number: ";
                std::cin >> j;
                if (j > 3 || j < 1) {
                    std::cout << "Error. Incorrect number. Try again." << std::endl;
                }
            } while (j > 3 || j < 1);
            j = j - 1;
            std::cout << "Please enter correct value: ";
            std::cin >> matrix[i][j];
            std::cout << "Now right?" << std::endl;
        }
    } while (a == 'n' || a != 'y');
    for (m = 0; m < 3; m++) {
        for (j = m; j < m + 1; j++) {
            if (m % 2 == 0) {
                fs[m] = matrix[0][j];
            }
            else {
                fs[m] = -matrix[0][j];
            }
        }
    }
    i = 0; j = -1; m = -1; l = -1;
    while (true) {
        m = m + 1;
        if (m == 3) { m = -1; break; }
        while (true) {
            i = i + 1;
            if (i == 3) { i = 0; break; }
            while (true) {
                j = j + 1;
                if (j == 3) { j = -1; l = -1; break; }
                else if (j == m) { continue; }
                l = l + 1;
                dsm[m][i - 1][l] = matrix[i][j];
            }
        }
    }
    for (m = 0; m < 3; m++) {
        i = 1; j = 1;
        pdet[m] = dsm[m][i - 1][j - 1] * dsm[m][i][j] - dsm[m][i - 1][j] * dsm[m][i][j - 1];
        det[m] = pdet[m] * fs[m];
    }
    determinant = det[0] + det[1] + det[2];
    std::cout << "Determinant is " << determinant << std::endl;
    return 0;
}