C++ array with random counts

Question

I am stuck somewhere(have some problem with the random number) and I know it, but can't find where to fix...

Two void functions must be used; void randomNumbers(int numbers[][3], int rowSize), void randomCounts(int numbers[][3], int size, int counts[])

I can't put images to show how it should and does look like in .exe files as I just signed up today ...... Hope this works ;(

Expected Result:

//========================
//     7      6      5
//     2      1      1
//     6      7      2
//     9      3      3
//     8      1      1
//========================

//Ran. Number:       0    1    2    3    4    5    6    7    8    9
//Frequency(Counts): 0    4    2    2    0    1    2    2    1    1

What I DID:

//========================
//     0      0      0
//     0      0      0
//     0      0      0
//     0      0      0
//     0      0      0
// ========================

// Ran. Number:       0    1    2    3    4    5    6    7    8    9
// Frequency(Counts): 001A148D

Code:

#include <iostream>
#include <iomanip>
#include <ctime>
using namespace std;

const int COL = 3;
const int SIZE = 5;

void randomNumbers(int inumbers[][3], int rowSize) {
    int num = 0;
    for (int i = 0; i < 10; i++) {
        num = rand() % 10;
    }
}

void randomCounts(int inumbers[][3], int size, int counts[]) {
    for (int i = 0; i < 10; i++) {
        counts[i]++;
        cout << setw(5) << counts[i];
    }
}

int main(){

    int random[SIZE][COL] = {};
    srand((unsigned)time(NULL));

    cout << endl;
    cout << "==================" << endl;

    for (int i = 0; i < SIZE; i++) {
        for (int j = 0; j < COL; j++) {
            cout << setw(5) << random[i][j];
            if (j == COL - 1) {
                cout << endl;
            }
        }
    }

    cout << "==================" << endl;
    cout << endl;


    cout << "Ran. Number: " << setw(5) << "0" << setw(5) << "1" << setw(5) << "2" << setw(5) << "3" << setw(5) << "4" << setw(5) << "5" << setw(5) << "6" << setw(5) << "7" << setw(5) << "8" << setw(5) << "9" << endl;
    cout << "Frequency(Counts): " << randomCounts << endl;



    return 0;
}

Welcome to Stack Overflow. What happens when you try to generate and print one random number? (And please show us the real code.) — Beta
– Beta, Commented Jun 10, 2020 at 11:16
@Beta I couldn't attach how it should appear in .exe as I am not allowed to attach image files. I edited the code just now. — xixxaxee
– xixxaxee, Commented Jun 10, 2020 at 11:22

Fantastic Mr Fox · Accepted Answer · 2020-06-10 11:27:41Z

1

Ok, so why are you getting 0, 0, 0.... Because you never actually call your functions. You initialize your array:

int random[SIZE][COL] = {};

Then you print it here:

cout << setw(5) << random[i][j];

And nowhere in between do you set anything into this array. When you do start calling your functions you will find they don't work, due to copying the input and doing some undefined behaviour. When you have debugged this a bit more, ask a new question.

answered Jun 10, 2020 at 11:27

Fantastic Mr Fox

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2 Comments

xixxaxee Over a year ago

I'm sorry if this sounds a bit awkward but I posted this as I didn't know how to call the func properly in main().... I thought of writing; for (int i ~~~) {for (int j ~~~) { random [i] [j] = randomNumbers(random, 5);}} But it wouldn't work as I tried to put void into int

Fantastic Mr Fox Over a year ago

You should add this detail to the question.

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