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double get_random(double min, double max) {
/* Returns a random double between min and max */
return min * ((double) rand() / (double) RAND_MAX) - max;
}
That's my function to generate random doubles between a min and a max. However, when I call get_random(-1.0, 1.0);, I get values between -2.0 and -1.0.
Any idea of what I'm doing wrong and how I can fix it?
490
In order to generate Random double type numbers in Java, we use the nextDouble() method of the java. util. Random class. This returns the next random double value between 0.0 (inclusive) and 1.0 (exclusive) from the random generator sequence.
The built-in function Math. random() creates a random value from 0 to 1 (not including 1 ). Write the function random(min, max) to generate a random floating-point number from min to max (not including max ).
The Random. NextDouble() method in C# is used to return a random floating-point number that is greater than or equal to 0.0, and less than 1.0.
Is it possible to generate a random number between 2 doubles? public double GetRandomeNumber (double minimum, double maximum) { return Random.NextDouble (minimum, maximum) } Any thoughts would be appreciated. Yes. Random.NextDouble returns a double between 0 and 1.
Random.NextDouble returns a double between 0 and 1. You then multiply that by the range you need to go into (difference between maximum and minimum) and then add that to the base (minimum). public double GetRandomNumber (double minimum, double maximum) { Random random = new Random (); return random.NextDouble () * (maximum - minimum) + minimum; }
public double GetRandomNumber(double minimum, double maximum) { Random random = new Random(); return random.NextDouble() * (maximum - minimum) + minimum; }. Real code should have random be a static member. This will save the cost of creating the random number generator, and will enable you to call GetRandomNumber very frequently.
Well, the Random class actually generates pseudo random numbers, with the “seed” for the randomizer being the system time. If your loop is sufficiently fast, the system clock time will not appear different to the randomizer and each new instance of the Random class would start off with the same seed and give you the same pseudo random number.
Shouldn't the formula be
(max - min) * ( (double)rand() / (double)RAND_MAX ) + min
(double)rand() / (double)RAND_MAX returns a random number between 0 and 1
(max - min) * ( (double)rand() / (double)RAND_MAX ) returns a random number between 0 and max - min.0 + min and min + (max-min) - i.e. min and max.
101
You can use this for generating random double or floating numbers:
((double) rand()*(max-min)/(double)RAND_MAX-min);
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