生成随机负NSInteger

Question

I'm trying to generate random negative NSInteger using the following code,

+ (NSInteger)getNegativeRandomNumber {
    uint32_t random = arc4random_uniform(2147483647); // where 2147483647 is the max 32-bit positive value returned by random function
    return (NSInteger)(-1 * random); // convert the positive into negative number
}

But occasionally this code gives me positive numbers. Do you see any issue with this code?

Answer 1

You get negative numbers with

return -(NSInteger)random;

You need first to cast to a signed type.

Answer 2

This will surely help....

-(int) generateRandomNumberWithlowerBound:(int)0
                               upperBound:(int) 2147483647
{
    int rndValue = lowerBound + arc4random() % (upperBound - lowerBound);
    return -(NSInteger)(rndValue);
}