Generate n random numbers whose sum is m and all numbers should be greater than zero

Question

I want to generate 9 non zero random numbers whose sum is 250. I have tried following code it gives me 9 random numbers but some numbers are zero.

 public vo         


        

Answer 1

Here's one way to do it, that avoids (most) magic numbers and provides a decent distribution of numbers though all will be smaller than other possible solutions.

public static void n_random(int count, int finalSum)
{
    Random r = new Random();
    int numbers[] = new int[count];
    int sum = 0;
    for (int i = 0; i < count - 1; i++)
    {
        numbers[i] = r.nextInt((finalSum - sum) / 2) + 1;
        sum += numbers[i];
    }
    numbers[count - 1] = finalSum - sum;

    StringBuilder numbersString = new StringBuilder("Random number list: ");
    for (int i = 0; i < count; i++)
        numbersString.append(numbers[i] + " ");
    System.out.println(numbersString);
}

public static void main(String[] args)
{
    n_random(9, 250);
}