Generate a series of random numbers that add up to N in c#

Question

How do I generate 30 random numbers between 1-9, that all add up to 200 (or some arbitrary N), in C#?

I\'m trying to generate a string of digits that can add togethe

Answer 1

This method will return 30 random numbers that add up to an arbitraryN. It is possible do, to have some 0 values. if that is not feasible, just initialize the array all to one's and if the sum is greater to the arbitraryN, set vals[nextIdx] to 1 instead of 0. Hope this helps.

    private int[] getNumbers(int arbitraryN) {
        int[] vals = new int[30];
        int nextIdx = 0;
        int nextNumber=0;
        Random r = new Random();
        if (arbitraryN > 270 || arbitraryN < 30)
            throw new Exception("Not a Valid number");
        while (vals.Sum() < arbitraryN)
        {
            nextNumber = r.Next(1, 9);
            nextIdx = r.Next(29);
            vals[nextIdx] = nextNumber;
            if (vals.Sum() > arbitraryN)
            {
                vals[nextIdx] = 0;
                vals[nextIdx] = 270 - vals.Sum();
                break;
            }
        }
        return vals;
    }