Помогите с с++

 #include <iostream>
#include <limits>
#include <random>
#include <vector>
 
using namespace std;
 
class Matrix {
    size_t n;
    vector<vector<int>> matrix;
    friend ostream& operator<<(ostream& out, const Matrix& mx) {
        for (const auto& row : mx.matrix) {
            for (auto value : row) out << value << ' ';
            out.put('\n');
        }
        return out;
    }
public:
    using result_t = pair<int, long long>;
    explicit Matrix(const size_t n)
        : n(n), matrix(n, vector<int>(n)) {}
    void fill_random(int l, int r) {
        if (r < l) swap(l, r);
        uniform_int_distribution uid(l, r);
        mt19937 gen{ random_device()() };
        for (auto& row : matrix) {
            for (auto& value : row) value = uid(gen);
        }
    }
    result_t tr() const {
        auto max = numeric_limits<int>::min();
        auto sum = 0LL;
        for (size_t i = 0; i < n; ++i) {
            for (size_t j = i; j < n; ++j) {
                if (max < matrix[i][j]) max = matrix[i][j];
                sum += matrix[i][j];
            }
        }
        return { max, sum };
    }
    result_t bl() const {
        auto max = numeric_limits<int>::min();
        auto sum = 0LL;
        for (size_t i = 0; i < n; ++i) {
            for (size_t j = 0; j <= i; ++j) {
                if (max < matrix[i][j]) max = matrix[i][j];
                sum += matrix[i][j];
            }
        }
        return { max, sum };
    }
    result_t tl() const {
        auto max = numeric_limits<int>::min();
        auto sum = 0LL;
        for (size_t i = 0; i < n; ++i) {
            for (size_t j = 0; j < n - i; ++j) {
                if (max < matrix[i][j]) max = matrix[i][j];
                sum += matrix[i][j];
            }
        }
        return { max, sum };
    }
    result_t br() const {
        auto max = numeric_limits<int>::min();
        auto sum = 0LL;
        for (size_t i = 0; i < n; ++i) {
            for (size_t j = n - 1 - i; j < n; ++j) {
                if (max < matrix[i][j]) max = matrix[i][j];
                sum += matrix[i][j];
            }
        }
        return { max, sum };
    }
};
 
void show_result(const char* prompt, const Matrix::result_t& result) {
    const auto& [max, sum] = result;
    cout << prompt << ". max: " << max << ", sum: " << sum << '\n';
}
 
int main() {
    cout << "n: ";
    size_t n;
    cin >> n;
    Matrix matrix(n);
    matrix.fill_random(10, 99);
    cout << matrix << '\n';
    show_result("A", matrix.tr());
    show_result("Б", matrix.bl());
    show_result("И", matrix.tl());
    show_result("К", matrix.br());
}