fill array with random but unique numbers in C# [duplicate]

Question

Okay I know there are few posts like this but I need to use only loops (for,do,while) and if, else to fill array with random but unique numbers so how shall i edit this code

        int[] x = new int[10];
        Random r = new Random();

        int i;
        for (i = 0; i < x.Length; i++) {

            x[i] = r.Next(10);
            Console.WriteLine("x[{0}] = {1}", i, x[i]);
        }

so I mean that when i randomize it wont repeat i used r.next(10) just because it was easier to spot whether it repeats or not so it shiuld use each number only once — user6055525
– user6055525, Commented Mar 13, 2016 at 17:37
If you have a target array length of 10, and only want numbers up to 10, then you actually just want to shuffle the array [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]. And that’s explained in the linked question. — poke
– poke, Commented Mar 13, 2016 at 17:41
no i need to increase random generated numbers limit from 0,100 i used 10 on code now just so it was easier that it doesn't repeat — user6055525
– user6055525, Commented Mar 13, 2016 at 17:43
Is 100 the final upper limit? Then create an array from 0…100, shuffle that, and take the first 10 numbers. That’s still more efficient than generating random numbers while checking all the time whether you already had that one or not. — poke
– poke, Commented Mar 13, 2016 at 17:50

Andrey Polyakov · Accepted Answer · 2016-03-13 19:14:47Z

1

You could check if the newly generated number already exists in the array, if not then add it to the array, if yes then generate a new one.

For examle:

class Program
{
    static void Main(string[] args)
    {
        int[] x = new int[10];
        Random r = new Random();

        int i;
        for (i = 0; i < x.Length; i++)
        {
            var next = 0;                
            while (true)
            {
                next = r.Next(10);
                if (!Contains(x, next)) break;                    
            }

            x[i] = next;
            Console.WriteLine("x[{0}] = {1}", i, x[i]);
        }

        Console.ReadLine();
    }

    static bool Contains(int[] array, int value)
    {
        for (int i = 0; i < array.Length; i++)
        {
            if (array[i] == value) return true;
        }
        return false;
    }
}

edited Mar 13, 2016 at 19:14

Andrey Polyakov

2431 silver badge9 bronze badges

answered Mar 13, 2016 at 17:53

Bogoljub

736 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user6055525 Over a year ago

can you please tell me how can i do it ?

SacWebDeveloper Over a year ago

This algorithm crashes Unity for some reason.

Andrey Polyakov · Accepted Answer · 2016-03-13 17:33:46Z

0

Without checking that generated number is already presented in array you can't to solve this task.

So you must generate new number and before inserting it into array check for uniq.

answered Mar 13, 2016 at 17:33

Andrey Polyakov

2431 silver badge9 bronze badges

1 Comment

user6055525 Over a year ago

how can i check if its unique ? what will the code be

Collectives™ on Stack Overflow

fill array with random but unique numbers in C# [duplicate]

2 Answers 2

2 Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Linked

Related