>> In C I just know int rand(void).
That's a good start.
>> But I do not see the possibility to limit the numbers to be choosen from 1 to 15.
rand returns a number between 0 and RAND_MAX. If you want to limit the range to a pre-specified one, there's an easy way to do that. You can generate a random number between x and y (x inclusive) like this :
x + (rand() % (y - x))
so, for values from 1 .. 15 :
1 + (rand() % 15)
>> I also do not see the possibility to avoid the repetition of the numbers sequence for a few times.
If you don't want repetition, you'll have to keep track of the values that have already been generated, and if one is generated again, just generate another one.
