Generate 50 random numbers and store them into an array c++

Question

this is what i have of the function so far. This is only the beginning of the problem, it is asking to generate the random numbers in a 10 by 5 group of numbers for the output, then after this it is to be sorted by number size, but i am just trying to get this first part down.

/* Populate the array with 50 randomly generated integer values
* in the range 1-50. */
void populateArray(int ar[], const int n) {
    int n;
    for (int i = 1; i <= length - 1; i++){

        for (int i = 1; i <= ARRAY_SIZE; i++) {
            i = rand() % 10 + 1;
            ar[n]++;
        }

    }
}

Please compile with maximum warning level. If you do so, your compiler should warn you that you are declaring a local variable n when another variable n already exists (you are thus hiding the parameter n). And you are using this uninitialized n in your line "ar[n]++". Also: what is length? What is ARRAY_SIZE? What is n supposed to be? — Werner Henze
– Werner Henze, Commented Oct 28, 2014 at 16:54

sh03 · Accepted Answer · 2014-10-28 17:10:27Z

1

First of all we want to use std::array; It has some nice property, one of which is that it doesn't decay as a pointer. Another is that it knows its size. In this case we are going to use templates to make populateArray a generic enough algorithm.

template<std::size_t N>
void populateArray(std::array<int, N>& array) { ... }

Then, we would like to remove all "raw" for loops. std::generate_n in combination with some random generator seems a good option.

For the number generator we can use <random>. Specifically std::uniform_int_distribution. For that we need to get some generator up and running:

std::random_device device;
std::mt19937 generator(device());
std::uniform_int_distribution<> dist(1, N);

and use it in our std::generate_n algorithm:

std::generate_n(array.begin(), N, [&dist, &generator](){ 
    return dist(generator); 
});

Live demo

answered Oct 28, 2014 at 17:10

sh03

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1 Comment

Pat Over a year ago

Thank you for the feedback, but the only problem with this is i was given main and all the functions already, we have to build the functions accordingly

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