generate 13 digit unique random number in c#

Question

Modify the follwing code to generate 13 digit unique random number in c#

public static string GenerateUniqueRandomNumbers()
    {
        Random generator = new Random();
        String r = generator.Next(0, 1000000).ToString("D6");
        if (r.Distinct().Count() == 1)
        {
            r = GenerateUniqueRandomNumbers();
        }
        return r;
    }

And what exactly is the problem you are having? Also note that this code doesn't generate a unique number either — Hans Keﬆing, Nov 19 '19 at 11:36
Does this answer your question? [How to generate a random 10 digit number in C#?](https://stackoverflow.com/questions/7055489/how-to-generate-a-random-10-digit-number-in-c) — Nauman Khan, Nov 19 '19 at 11:37

score 0 · Answer 1 · answered Nov 19 '19 at 12:43

0

Very malformed question

IF your problem is that maxValue cannot have 13 digit, a quick workaround could be concatenate 2 strings

    String r = generator.Next(0, 1000000).ToString("D6");
    r += generator.Next(0, 10000000).ToString("D7");

answered Nov 19 '19 at 12:43

Lorenzo

91
5

score 0 · Answer 2 · answered Nov 19 '19 at 12:54

For 13 digits we need long variable but Random.Next method does not support long dataType it only support Integer data type. Hence , we have to do something tricky.

Check the below code to generate generate 13 digit number.

    Random generator = new Random();
    String r = generator.Next(0, 999999).ToString("D13");

Note: I have used ToString("D13") to get the 13 digits value.

score 0 · Answer 3 · answered Nov 20 '19 at 07:21

0

public static string GenerateUniqueRandomNumbers()
    {
        Random generator = new Random();
        String r = generator.Next(0, 1000000).ToString("D6");
        r += generator.Next(0, 10000000).ToString("D7");
        if (r.Distinct().Count() == 1)
        {
            r = GenerateUniqueRandomNumbers();
        }
        return r;
    }

answered Nov 20 '19 at 07:21

hornet

5
2
5

That `if (r.Distinct().Count() == 1)` only blocks numbers that are using just 1 digit (like 11111). It doesn't know about previously generated 13-digit number strings – Hans Keﬆing Nov 27 '19 at 10:59

score 0 · Answer 4 · answered Aug 07 '22 at 12:33

    Random generator = new Random();
    string s = "380003562";
    s += generator.Next(0, 0000000).ToString("D"+(13-s.Length).ToString());

With this code, if you are using an existing number, you can quickly bring it to 13 digits or any digit number you want.

generate 13 digit unique random number in c#

4 Answers4