Class-matrix with random values

Question

Class-matrix with random values

The goal is to create a matrix class that can create two-dimensional arrays of specified sizes, but with random values. The array is created, but I get the same values every time. Please tell me what the problem is?

#include <iostream>
#include <time.h>
#include <iomanip>

using namespace std;

class Matrix
{
private:

int str;
int col;
int **mat;
public:
Matrix(int str, int col)      //конструктор класса
{
    this -> str = str;
    this -> col = col;
    mat = new int*[str];
    for (int i = 0; i < str; i++)
    {
        mat[i] = new int[col];
    }
    cout << "Конструктор " << this << endl;

}   

void FillMatrix()     //метод заполнения
{
    srand(time(NULL));
    for (int i = 0; i < str; i++)
    {
        for (int j = 0; j < col; j++)
        {
            mat[i][j] = rand() %10;
        }
    }
}

void PrintMatrix()       //вывод
{

    for (int i = 0; i < str; i++)
    {
        for (int j = 0; j < col; j++)
        {
            cout << setw(4) << mat[i][j];
        }
        cout << endl;
    }
    cout << endl;
}

~Matrix()        //деструктор, я его должен дописать. 
{
delete[]mat;
        cout << "Destruct" << this << endl << endl;
}


};

int main()
{
setlocale(LC_ALL, "ru");

Matrix a(3, 3);
Matrix b(3, 3);


b.FillMatrix();
a.FillMatrix();

a.PrintMatrix();
b.PrintMatrix();
}

0

c++динамические-массивы классы случайные-числа матрицы

Author: Yaant, 2018-11-14

Source

1 answers

score 0 · Accepted Answer

Hence:

For any other value passed through the seed parameter, and used when calling the srand function, the generation algorithm pseudo-random numbers can generate different numbers with each a subsequent call to the rand function. If you use the same thing the value of seed, with each call to the function rand, the generation algorithm pseudo-random numbers will generate the same a sequence of numbers.

I would do so:

#include <random>

class Matrix
{
private:
    std::mt19937 random_generator_;
    std::uniform_int_distribution<std::uint8_t> rand_uid(0, 9);
public:
    Matrix()      //конструктор класса
    {
        std::random_device random_device;
        random_generator_.seed(random_device()); 
    }   

    void FillMatrix()     //метод заполнения
    {
        for (int i = 0; i < str; i++)
        {
            for (int j = 0; j < col; j++)
            {
                mat[i][j] = rand_uid(random_generator_));
            }
        }
    }
};