Random array generation with no duplicates

Question

I am trying to create something that generates a random array with no duplicate values. I\'ve already looked at other answers but none seem to help me understand. I cannot t

Answer 1

In c++, all you need is:

std::random_shuffle()

http://www.cplusplus.com/reference/algorithm/random_shuffle/

int numbers [4];

for (int x=0; x!=4;x++)
{
    numbers[x] = x;
}

std::random_shuffle(numbers, numbers +4);

Update: OK, I had been thinking that a suitable map function could go from each index to a random number, but thinking again I realize that may be hard. The following should work:

    int size = 10;
    int range = 100;

    std::set sample;

    while(sample.size() != size)
        sample.insert(rand() % range); // Or whatever random source.

    std::vector result(sample.begin(), sample.end());

    std::random_shuffle ( result.begin(), result.end() );