Fill a two-dimensional array with random numbers and print their sum?

Question

C++ / C#

Hello everyone, I played tricks here with the "program". The task was as follows: given a two-dimensional array 3x3, fill it with random and calculate the sum of all elements of the array. I wrote something, but in my opinion it does not work correctly. Can you please tell me where is the mistake?

#include "stdafx.h"
#include "stdlib.h"
#include "time.h"
#include "iostream"
#include "conio.h"
#include "ctime"
using namespace std;


void main()
{
    int mas[3][3];
    int i, j, sum;

    srand(time(NULL));
    sum = 0;
    for (i = 0; i < 3; i++) 
    {
        for (j = 0; j < 3; j++) 
        {
            mas[i][j] = 0 + rand();
            sum = sum + mas[i][j];

        }
    }

    cout << mas[i][j] << endl;
    cout << sum << endl;
    _getch();

}

Answer 1

wrong here is
cout << mas[i][j] << endl;
it needs to be inserted inside the cycle for j
otherwise it looks normal.
it is not very clear why add 0

Answer 2

If you are talking about the fact that negative amounts can be displayed, it is because of the overflow when it rand()generates large numbers. For beauty, you can generate numbers up to one hundred, for example.

#include <iostream>

using namespace std;

int main()
{
    int mas[3][3];
    int i, j, sum;

    srand(time(NULL));
    sum = 0;
    for (i = 0; i < 3; i++) 
    {
        for (j = 0; j < 3; j++) 
        {
            mas[i][j] = rand() % 100;
            sum = sum + mas[i][j];
            cout << mas[i][j] << "\t";
        }
        cout << endl;
    }

    cout << "sum: " << sum << endl;
    cin.get();
}

When run it will output something like this

$ g++ -pedantic -Wall -Wextra test.c
$ ./a.out 
97	40	3	
32	81	26	
30	15	6	
sum: 330

In general, it would be nice to write what exactly works wrong in the question. There are no psychics here