C# – Random Password Generator – Video

Posted on August 7, 2013 by

I know a lot of people, having problems creating passwords. With the current code I will show you how to create a password using C#. The password consists of at least two capital letters, two small letters, a digit and three special characters. Furthermore, up to seven more chars are added, thus making its lenght a random between 8 and 15. Thus it is probably one of the best passwords ever, except for the fact it will be quite difficult for you to remember it.

Here is the code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class RandomPWDGerenrator
{
     private const string CapitalLetters = "QWERTYUIOPASDFGHJKLZXCVBNM";
     private const string SmallLetters = "qwertyuiopasdfghjklzxcvbnm";
     private const string Digits = "0123456789";
     private const string SpecialCharacters = "!@#$%^&*()-_=+<,>.";
     private const string AllChars = CapitalLetters+SmallLetters+Digits+SpecialCharacters;
     private static Random rnd = new Random();

    static void Main()
    {
        StringBuilder password = new StringBuilder();
        for (int i = 1; i <= 2; i++)
			{
			 char capitalLeter = GenerateChar(CapitalLetters);
             InsertAtRandomPositons(password,capitalLeter);
			}
        for (int i = 1; i <= 2; i++)
			{
			 char smallLetter = GenerateChar(SmallLetters);
             InsertAtRandomPositons(password,smallLetter);
			}
        char digit = GenerateChar(Digits);
        InsertAtRandomPositons(password, digit);

        for (int i = 1; i <= 3; i++)
			{
			 char specialChar = GenerateChar(SpecialCharacters);
            InsertAtRandomPositons(password,specialChar);
			}
        int count = rnd.Next(8);
        for (int i = 1; i <= count; i++)
			{
			    char specialChar = GenerateChar(AllChars);
                InsertAtRandomPositons(password,specialChar);
			}
        Console.WriteLine("Your New Password is:");
        Console.WriteLine(password);
        Console.WriteLine("Your password consists of {0} elements.",password.Length);
        Console.WriteLine();
        Console.WriteLine();
    }
    private static void InsertAtRandomPositons(StringBuilder password, char character)
    {
        int randomPosition = rnd.Next(password.Length+1);
        password.Insert(randomPosition,character);
    }
    private static char GenerateChar (string availableChars)
    {
        int randomIndex = rnd.Next(availableChars.Length);
        char randomChar = availableChars[randomIndex];
        return randomChar;
    }
}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

class RandomPWDGerenrator

{

private const string CapitalLetters = "QWERTYUIOPASDFGHJKLZXCVBNM";

private const string SmallLetters = "qwertyuiopasdfghjklzxcvbnm";

private const string Digits = "0123456789";

private const string SpecialCharacters = "!@#$%^&*()-_=+<,>.";

private const string AllChars = CapitalLetters+SmallLetters+Digits+SpecialCharacters;

private static Random rnd = new Random();

static void Main()

{

StringBuilder password = new StringBuilder();

for (int i = 1; i <= 2; i++)

{

char capitalLeter = GenerateChar(CapitalLetters);

InsertAtRandomPositons(password,capitalLeter);

}

for (int i = 1; i <= 2; i++)

{

char smallLetter = GenerateChar(SmallLetters);

InsertAtRandomPositons(password,smallLetter);

}

char digit = GenerateChar(Digits);

InsertAtRandomPositons(password, digit);

for (int i = 1; i <= 3; i++)

{

char specialChar = GenerateChar(SpecialCharacters);

InsertAtRandomPositons(password,specialChar);

}

int count = rnd.Next(8);

for (int i = 1; i <= count; i++)

{

char specialChar = GenerateChar(AllChars);

InsertAtRandomPositons(password,specialChar);

}

Console.WriteLine("Your New Password is:");

Console.WriteLine(password);

Console.WriteLine("Your password consists of {0} elements.",password.Length);

Console.WriteLine();

}

private static void InsertAtRandomPositons(StringBuilder password, char character)

{

int randomPosition = rnd.Next(password.Length+1);

password.Insert(randomPosition,character);

}

private static char GenerateChar (string availableChars)

{

int randomIndex = rnd.Next(availableChars.Length);

char randomChar = availableChars[randomIndex];

return randomChar;

}

What is interesting in this code:

1. We have the variable “rnd” defined in the class, and not in the Main method, thus making it available for the whole class.

2. The Method GenerateChar() returns a random symbol. The method chooses a random position in a variety of symbols and returns the symbol of this position.

3. The method InsertAtRandomPosition() chooces a random position in the StringBuilder object and puts at this position a symbol.

Here is the video:

Disclaimer: The code is partially taken from the TelerikAcademy courses for programming & the free Bulgarian C# programming book.

You may find the exe file of this application here.