Question

I’m trying to generate 3 random numbers between 0 to 25. I used arc4random_uniform(25) for this and it generate 3 random numbers.but problem is that some time I get two or even all three numbers are same, but I require 3 unique numbers.

Answer 1

As @Thilo said you have to check they are random and repeat if they are not:

// This assumes you don't want 0 picked
u_int32_t numbers[3] = { 0, 0, 0 };
for (unsigned i = 0; i < 3; i++)
{
    BOOL found = NO;
    u_int32_t number;
    do
    {
        number = arc4random_uniform(25);
        if (i > 0)
            for (unsigned j = 0; j < i - 1 && !found; j++)
                found = numbers[j] == number;
    }
    while (!found);
    numbers[i] = number;
}