May 5, 2011 · The first solution is to use the java.util.Random class: import java.util.Random; Random rand = new Random(); // Obtain a number between [0 - 49]. int n = rand.nextInt(50); // Add 1 to the result to get a number from the required range // (i.e., [1 - 50]). n += 1; Another solution is using Math.random(): double random = Math.random() * 49 + 1 ...

To generate a random number "in between two numbers", use the following code: Random r = new Random(); int lowerBound = 1; int upperBound = 11; int result = r.nextInt(upperBound-lowerBound) + lowerBound; This gives you a random number in between 1 (inclusive) and 11 (exclusive), so initialize the upperBound value by adding 1.

Mar 22, 2011 · To generate a 6-digit number: Use Random and nextInt as follows: Random rnd = new Random(); int n = 100000 + rnd.nextInt(900000); Note that n will never be 7 digits (1000000) since nextInt(900000) can at most return 899999. So how do I randomize the last 5 chars that can be either A-Z or 0-9? Here's a simple solution:

Mar 11, 2011 · The first (100) is the number I am ADDING to the random one. This means that the new output number will be the random number + 100. numGen.nextInt() is the value of the random number itself, and because I put (100) in its parentheses, it is any number between 1 and 100. So when I add 100, it becomes a number between 101 and 200.

Generate random number between 1 to 100 as position and return array[position-1] to get the value . Once you use a number in array, mark the value as -1 ( No need to maintain another array to check if this number is already used) If value in array is -1, get the random number again to fetch new location in array.

Apr 23, 2015 · With Java 7, one can use ThreadLocalRandom.. A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is initialized with an internally generated seed …

I tried to make this as simple as possible in Java. This makes an integer array of 100 variables and fill it with integers between 0 and 10 using only three lines of code. You can easily change the bounds of the random number too!

Get Random number Returns a random integer x satisfying lower <= x <= upper. If lower > upper, returns 0. @param lower @param upper @return. In the main method I created list then i check if the random number exist on the list if it doesn't exist i will add the random number to the list. It is very slow but straight forward.

Oct 27, 2011 · This same protection persists for all numbers, even if you got the same number 5 times in a row. E.g., if the random number generator gave you 0 five times in a row, the results would be: [ 0, 19, 18, 17, 16 ]. You would never get the same number twice.

@ataulm: In older versions of Java creating multiple Random objects didn't guarantee randomness. "Two Random objects created within the same millisecond will have the same sequence of random numbers." . In newer versions it is probably OK, but I didn't know that when I wrote my comment three years ago. –