How To Create Random Password Of Given Length Using C#

Here I have written the code to create random Password/Number using uppercase, lowercase, digits, and special characters.

.Net provides the class Random , which has three methods - Next, NextBytes, and NextDouble.

• Next()- Next method returns a random number.
• NextBytes()-NextBytes returns an array of bytes filled with random numbers.
• NextDouble()- returns a random number between 0.0 and 1.0.

I have used NextDouble.

Use

We can use this random password for One Time Password (OTP) or Temporary Password.

Code written in Console Application

//Libraries
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace PasswordPractice {
    class PasswordCreate {
        //Tis function is making the Random Password
        public string makeRandomPassword(int length) {
            string UpperCase = "QWERTYUIOPASDFGHJKLZXCVBNM";
            string LowerCase = "qwertyuiopasdfghjklzxcvbnm";
            string Digits = "1234567890";
            string allCharacters = UpperCase + LowerCase + Digits;
            //Random will give random charactors for given length
            Random r = new Random();
            String password = "";
            for (int i = 0; i < length; i++) {
                double rand = r.NextDouble();
                if (i == 0) {
                    password += UpperCase.ToCharArray()[(int) Math.Floor(rand * UpperCase.Length)];
                } else {
                    password += allCharacters.ToCharArray()[(int) Math.Floor(rand * allCharacters.Length)];
                }
            }
            Console.WriteLine(password);
            Console.ReadLine();
            return password;
        }
        static void Main(string[] args) {
            //User Input
            Console.WriteLine("Enter length of password");
            string len = Console.ReadLine();
            PasswordCreate n = new PasswordCreate();
            //Call the method in main method
            n.makeRandomPassword(Convert.ToInt32(len));
        }
    }
}

Output of Given Code



I have uploaded the same as an attachment. Please download and make changes accordingly.