Help with generating random number

[dullboy]

If I want to generate 10 random numbers ranging from 0 to 9, is it possible to have 10 different numbers every time? For example, every time they should be like this, 1,3,4,9,0,2,8,7,5,6 without duplicate. I tried srand and rand but it looks like it doesn't work. They simply will generate duplicate numbers. Thanks for your inputs.

[laserlight]

Yes, by shuffling a container of those numbers.

[monarch_dodra]

http://www.cplusplus.com/reference/a...andom_shuffle/

You'll even notice that the example is your problem (minus the 0).

[dullboy]

Thanks for your inputs. I guess you meant random_shuffle. But random_shuffle generates the same result every time. I wonder if it is possible to generate different result every time by using random_shuffle. It looks like it doesn't accept seed. Thanks for your inputs.

Yes, by shuffling a container of those numbers.

[GCDEF]

Thanks for your inputs. I guess you meant random_shuffle. But random_shuffle generates the same result every time. I wonder if it is possible to generate different result every time by using random_shuffle. It looks like it doesn't accept seed. Thanks for your inputs.

I tried the example in the link above. It generates different numbers for me.

[superbonzo]

I tried the example in the link above. It generates different numbers for me.

unfortunately, random_shuffle is not guaranteed neither to seed itself nor to use rand internally, therefore using srand() will have no effect in general. So, you should specify your own random number generator in the random_shuffle call.

EDIT: oh sorry, I didn't realized that the example in the link already covered the user provided random generator case ...

[aamir121a]

Computers cannot generate random number , because behind each rand() algorithm there a sequence , for further reading pls. see this

http://en.wikipedia.org/wiki/Random_number_generation

[dullboy]

http://www.cplusplus.com/reference/a...andom_shuffle/

You'll even notice that the example is your problem (minus the 0).

That is a good example. How does p_myrandom work in the example? It looks like p_myrandom is a function pointer applied to each element of the vector. But how'd I understand i in the definition of myrandom?Thanks for your inputs.

[yohosuff]

You could try this:

srand(time(0));

int a[10] = {0};
int n;
bool duplicate;
bool loop;

for(int i = 0; i <= 9; ++i)
{
    loop = true;
    while(loop)
    {
        n = 1+rand()%10;
        duplicate = false;
        for(int j = 0; j <= 9; ++j)
        {
            if(a[j] == n)
                duplicate = true;
        }
        if(duplicate == false)
        {
            a[i] = n;
            loop = false;
        }
    }
}