Question

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Non repeating random numbers in Objective-C

How to generate non repeating random numbers?

I saw this on many sites but they give in main.c file code.

When I use the main.c file the code working is fine, but when I try to convert in to my.m file it is not working.

example:

I need to get all the numbers between 0-10 randomly.and the numbers should not repeat again.

Answer 1

Use arc4random()
Example:

- (NSData *)randomBytes:(size_t)count
{
    NSMutableData *data = [NSMutableData dataWithLength:count];

    SecRandomCopyBytes( kSecRandomDefault,
                        data.length,
                        data.mutableBytes);
    return data;
}

It turns out that getting a random number in a range is not as simple as using mod.

- (u_int32_t)randomInRangeLo:(u_int32_t)loBound toHi:(u_int32_t)hiBound
{
    u_int32_t random;
    int32_t   range = hiBound - loBound + 1;
    u_int32_t limit = UINT32_MAX - (UINT32_MAX % range);

    do {
        random = arc4random();
    } while (random > limit);

    return loBound + (random % range);
}