random uppercase in a word + multiple string insert - c#

I really need a solution for the next scenario(I've been searching for hours and beating about the bushes to find a smooth solution, but none worked):
I have a winform that:
parse a text file
generate some folders using random words from that file
My code so far:
int value;
string path = null;
private void button1_Click(object sender, EventArgs e)
{
FolderBrowserDialog fbd = new FolderBrowserDialog();
if (fbd.ShowDialog(this) == DialogResult.OK)
{
path = fbd.SelectedPath;
}
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
value = Convert.ToInt32(textBox1.Text);//store the value from the textbox in variable "value"
}
private void button2_Click(object sender, EventArgs e)
{
if (path != null && Directory.Exists(path))
for (int i = 0; i < value; i++)
{
Random rnd = new Random();
string tick1 = rnd.Next(0, 10).ToString();
var lines = File.ReadAllLines(#"M:\\dictionar.txt");
var r = new Random(DateTime.Now.Millisecond);
var randomLineNumber = r.Next(0, lines.Length - 1);
var line = lines[randomLineNumber];
StringBuilder b = new StringBuilder();
for (int j = 0; j < line.Length; j++)
{
char c = line[j];
if (rnd.Next(2) == 0)
{
c = Char.ToUpper(c);
}
b.Append(c);
if (j % 3 == 2)
{
b.Append(rnd.Next(10));
}
}
line = b.ToString();
Directory.CreateDirectory(Path.Combine(path, string.Format("{0}", line.Insert(2, tick1).Insert(4, tick1).Insert(6, tick1))));
}
}
Is there a way to use ToUpper() method as line.Insert() one so that I can get random upper letters? More, is there a better way of randomizing those index positions form line.Insert() (I'm asking this because when it's generating the folders name: the indexes are the same: e.g pe8rs8on8al and just after that the index changes.)?
I want to achieve the following:
if I have the next words in the .txt file:
personal
football
programming
computer
I would like the folder names to look like:
Pe3rs9oN1al
fO8ot5Ba6lL


You can loop through the characters in the string and build a new string depending on random values:
StringBuilder b = new StringBuilder();
for (int i = 0; i < line.Length; i++ ) {
char c = line[i];
if (rnd.Next(2) == 0) {
c = Char.ToUpper(c);
}
b.Append(c);
if (i % 2 == 1) {
b.Append(rnd.Next(10));
}
}
line = b.ToString();
Note: You shouldn't create Random objects in the loop. You should create a single Random object before the loop and use for all random numbers that you need. Creating instances too close in time will make them return the same sequences of random numbers. Also, you don't need to seed the random generator from the clock, the constructor without parameters does that automatically:
Random rnd = new Random();
So, the code in the method would be:
if (path != null && Directory.Exists(path))
Random rnd = new Random();
for (int i = 0; i < value; i++)
{
var lines = File.ReadAllLines(#"M:\\dictionar.txt");
var randomLineNumber = rnd.Next(0, lines.Length);
var line = lines[randomLineNumber];
StringBuilder b = new StringBuilder();
for (int j = 0; j < line.Length; j++)
{
char c = line[j];
if (rnd.Next(2) == 0)
{
c = Char.ToUpper(c);
}
b.Append(c);
if (j % 2 == 1)
{
b.Append(rnd.Next(10));
}
}
line = b.ToString();
Directory.CreateDirectory(Path.Combine(path, line));
}
}
Note the rnd.Next(0, lines.Length) to pick a random line. The upper limit for the random number is not inclusive, so if you use rnd.Next(0, lines.Length - 1) it will never pick the last line.


That's because you are specifying only tick1 in the same loop. If you want to change this, add additional ticks to your code as below:
string tick1 = rnd.Next(0, 10).ToString();
string tick2 = rnd.Next(0, 10).ToString();
string tick3 = rnd.Next(0, 10).ToString();
Then use those in your formatting of the string:
Directory.CreateDirectory(Path.Combine(path, string.Format("{0}", line.Insert(2, tick1).Insert(4, tick2).Insert(6, tick3))))


Like Guffa said you should not use Random in a loop, in all preference you should only instanciate one of it, but I think you could use it like this
public static class StringRandomize
{
static readonly Random rnd = new Random();
static char[] permmitedCharacters { get; set; }
static StringRandomize()
{
List<char> Chars= new List<char>();
for (int i = 48; i < 48+10; i++)
{
Chars.Add((char)i);
}
for (int i = 65; i < 65+26; i++)
{
Chars.Add((char)i);
}
permmitedCharacters = Chars.ToArray();
}
public static string Randomize(string input, double RandomizePercent = 30)
{
StringBuilder result = new StringBuilder();
int index = 0;
while (index < input.Length)
{
if (rnd.Next(0, 100) <= RandomizePercent)
{
if (rnd.Next(0, 100) <= RandomizePercent)
{
result.Append(GenerateCaracter());
}
else
{
if (rnd.Next(0, 100) > 50)
{
result.Append(input.ToLower()[index]);
}
else
{
result.Append(input.ToUpper()[index]);
}
index++;
}
}
else
{
result.Append(input[index]);
index++;
}
}
return result.ToString();
}
private static char GenerateCaracter()
{
return permmitedCharacters[rnd.Next(0, permmitedCharacters.Length)];
}
}
private static void GenerateRandomDirectories(string path, int value)
{
//I'm supposing value is the number of lines that you want
var lines = File.ReadAllLines(#"M:\\dictionar.txt");
Random rnd = new Random();
if (path != null && Directory.Exists(path))
{
for (int i = 0; i < value; i++)
{
Directory.CreateDirectory(path + "\\" + StringRandomize.Randomize(lines[rnd.Next(0,lines.Length)]));
}
}
}
"pers3o7Nal"
"foOtBaLl"


Got like this
public Form1()
{
InitializeComponent();
string content = "";
using (FileStream fs = new FileStream("D:\\names.txt", FileMode.Open, FileAccess.Read))
using (StreamReader sr = new StreamReader(fs))
content = sr.ReadToEnd();
string[] names = content.Split(new string[] { "\r\n", "\r", "\n" }, StringSplitOptions.RemoveEmptyEntries);
string path = "D:\\RandDirs";
if (!Directory.Exists(path))Directory.CreateDirectory(path) ;
for (int i = 0; i < 50; i++) Directory.CreateDirectory(path + "\\" + getRandomName(names));
}
Random randName = new Random();
Random insertingNumber = new Random();
Random randUpper = new Random();
Random randInsertNumber = new Random();
string getRandomName(string[] names)
{
string name = names[randName.Next(names.Length)];
name = name.Replace(" ", "");
string result = "";
for (int i = 0; i < name.Length; i++)
result += (randUpper.Next(0, 9) <= 5 ? name[i].ToString().ToLower() : name[i].ToString().ToUpper())
+ (((i + 1) % 2 == 0) ? insertingNumber.Next(0, 9).ToString() : "");
return result;
}
as per your needs, i've changed from randomly inserting numbers to inserting number every 2 characters.

Related

C# Remove An Empty Character Array

I have character arrays seperated into multiple groups, my code uses a character from every group, so once character in a group is processed it will go to the next. I want to remove a group when it's considered empty. (or alternative if you can help fix the code so it skips empty groups)
In the form, there are checkboxes which add the specific characters to their specified group, you have the option to add those characters of choice or not, which I also have a user include input textbox if they want to add their personal characters, but in a case of a char group being empty I get an exception most likely due to the group having no characters.
Exception:
"System.IndexOutOfRangeException: 'Index was outside the bounds of the
array."
For
"result[i] = charGroups[nextGroupIdx][nextCharIdx];"
char[][] charGroups = new char[][]
{
CapitalCharacterSet.ToCharArray(),
LowercaseCharacterSet.ToCharArray(),
NumbersCharacterSet.ToCharArray(),
IncludeCharacterSet.ToCharArray(),
SpecialCharacterSet.ToCharArray()
};
FULL CODE:
char[][] charGroups = new char[][]
{
CapitalCharacterSet.ToCharArray(),
LowercaseCharacterSet.ToCharArray(),
NumbersCharacterSet.ToCharArray(),
IncludeCharacterSet.ToCharArray(),
SpecialCharacterSet.ToCharArray()
};
int[] charsLeftInGroup = new int[charGroups.Length];
for (int i = 0; i < charsLeftInGroup.Length; i++)
charsLeftInGroup[i] = charGroups[i].Length;
int[] leftGroupsOrder = new int[charGroups.Length];
for (int i = 0; i < leftGroupsOrder.Length; i++)
leftGroupsOrder[i] = i;
byte[] randomBytes = new byte[4];
RNGCryptoServiceProvider rng = new();
rng.GetBytes(randomBytes);
int seed = BitConverter.ToInt32(randomBytes, 0);
Random random = new(seed);
char[] result = null;
result = new char[length.Value];
int nextCharIdx;
int nextGroupIdx;
int nextLeftGroupsOrderIdx;
int lastCharIdx;
int lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;
for (int i = 0; i < result.Length; i++)
{
if (lastLeftGroupsOrderIdx == 0)
nextLeftGroupsOrderIdx = 0;
else
nextLeftGroupsOrderIdx = random.Next(0, lastLeftGroupsOrderIdx);
nextGroupIdx = leftGroupsOrder[nextLeftGroupsOrderIdx];
lastCharIdx = charsLeftInGroup[nextGroupIdx] - 1;
if (lastCharIdx == 0)
nextCharIdx = 0;
else
nextCharIdx = random.Next(0, lastCharIdx + 1);
try
{
result[i] = charGroups[nextGroupIdx][nextCharIdx];
}
catch
{
if (lastCharIdx == 0)
nextCharIdx = 0;
else
nextCharIdx = random.Next(0, lastCharIdx + 1);
}
if (lastCharIdx == 0)
charsLeftInGroup[nextGroupIdx] = charGroups[nextGroupIdx].Length;
else
{
if (lastCharIdx != nextCharIdx)
{
char temp = charGroups[nextGroupIdx][lastCharIdx];
charGroups[nextGroupIdx][lastCharIdx] =
charGroups[nextGroupIdx][nextCharIdx];
charGroups[nextGroupIdx][nextCharIdx] = temp;
}
charsLeftInGroup[nextGroupIdx]--;
}
if (lastLeftGroupsOrderIdx == 0)
lastLeftGroupsOrderIdx = leftGroupsOrder.Length - 1;
else
if (lastLeftGroupsOrderIdx != nextLeftGroupsOrderIdx)
{
int temp = leftGroupsOrder[lastLeftGroupsOrderIdx];
leftGroupsOrder[lastLeftGroupsOrderIdx] =
leftGroupsOrder[nextLeftGroupsOrderIdx];
leftGroupsOrder[nextLeftGroupsOrderIdx] = temp;
}
lastLeftGroupsOrderIdx--;
}
}

Make a password generator

I am currently trying to make a random password generator.
My code works fine if I only pick one type of symbols.
What's the best way to make my code to word for more than one type?
Also what parameters would you add to make the password more secured?
I am thinking of adding an if loop to check if there are more than two same letters, symbols or numbers in a row.
That's how my interface looks like:
and that is my code:
public partial class Form1 : Form
{
// Max number of identical characters in a row
const int Maximum_Identical = 2;
// lower case chars
const string lower_chars = "abcdefghijklmnopqrstuvwxyz";
// capital chars
const string capital_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
// numbers
const string numbers = "0123456789";
// symbols
const string symbols = #"!#$%&*#\";
// password lenght
int lenght;
private void button1_Click(object sender, EventArgs e)
{
//use stringbuilder so I can add more chars later
StringBuilder password = new StringBuilder();
//take max lenght from numericUpDown
lenght = Convert.ToInt32(numericUpDown1.Value);
// random instance so I can use Next and don't get loops
Random rdm = new Random();
if (small_letters__Box.Checked)
{
//add a random small character to pass untill it reaches the selected lenght
while (lenght-- > 0 )
{
password.Append(lower_chars[rdm.Next(lower_chars.Length)]);
}
}
if (capital_letters__Box.Checked)
{
//add a random capital character to pass untill it reaches the selected lenght
while (lenght-- > 0)
{
password.Append(capital_chars[rdm.Next(capital_chars.Length)]);
}
}
if (numbers_Box.Checked)
{
//add a random character to pass untill it reaches the selected lenght
while (lenght-- > 0)
{
password.Append(numbers[rdm.Next(numbers.Length)]);
}
}
if (symbols_Box.Checked)
{
//add a random character to pass untill it reaches the selected lenght
while (lenght-- > 0)
{
password.Append(symbols[rdm.Next(symbols.Length)]);
}
}
textBox1.Text = password.ToString();
}
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
}
}

Your password generation has 2 steps.
Determine the character set
Create a password randomly from the character set of length n
Function 1 creates the character set:
// Make sure you have using System.Linq;
private List<char> GetCharacterSet()
{
IEnumerable<char> returnSet = new char[]{};
if (small_letters__Box.Checked)
{
returnSet = returnSet.Append(lower_chars);
}
if (capital_letters__Box.Checked)
{
returnSet = returnSet.Append(capital_chars);
}
if (numbers_Box.Checked)
{
returnSet = returnSet.Append(numbers);
}
if (symbols_Box.Checked)
{
returnSet = returnSet.Append(symbols);
}
return returnSet.ToList();
}
Function 2 creates a password of given length from your character set
private string GetPassword(int length, List<char> characterSet)
{
if(characterSet.Count < 1)
{
throw new ArgumentException("characterSet contains no items!");
}
if(length < 1)
{
return "";
}
Random rdm = new Random();
StringBuilder password = new StringBuilder();
for(int i = 0; i < length; i++){
int charIndex = rdm.Next(0, characterSet.Count)
password.Append(characterSet[charIndex]);
}
return password.ToString();
}
Then simply rig your button click event handler to call these functions and display the resulting password.

below code is my already written code which I wrote more than a couple of years ago and I still use it in my many of my projects where needed, it covers all you are in need of
using System;
using System.Collections.Generic;
using System.Diagnostics.Contracts;
using System.Linq;
using System.Text;
using System.Threading;
public static class ArrayExtentions
{
public static object[] Shuffle(this object[] array)
{
var alreadySwaped = new HashSet<Tuple<int, int>>();
var rndLoopCount = RandomUtils.GetRandom(Convert.ToInt32(array.Length / 4), Convert.ToInt32((array.Length / 2) + 1));
for (var i = 0; i <= rndLoopCount; i++)
{
int rndIndex1 = 0, rndIndex2 = 0;
do
{
rndIndex1 = RandomUtils.GetRandom(0, array.Length);
rndIndex2 = RandomUtils.GetRandom(0, array.Length);
} while (alreadySwaped.Contains(new Tuple<int, int>(rndIndex1, rndIndex2)));
alreadySwaped.Add(new Tuple<int, int>(rndIndex1, rndIndex2));
var swappingItem = array[rndIndex1];
array[rndIndex1] = array[rndIndex2];
array[rndIndex2] = swappingItem;
}
return array;
}
}
public class RandomUtils
{
private static readonly ThreadLocal<Random> RndLocal = new ThreadLocal<Random>(() => new Random(GetUniqueSeed()));
private static int GetUniqueSeed()
{
long next, current;
var guid = Guid.NewGuid().ToByteArray();
var seed = BitConverter.ToInt64(guid, 0);
do
{
current = Interlocked.Read(ref seed);
next = current * BitConverter.ToInt64(guid, 3);
} while (Interlocked.CompareExchange(ref seed, next, current) != current);
return (int)next ^ Environment.TickCount;
}
public static int GetRandom(int min, int max)
{
Contract.Assert(max >= min);
return RndLocal.Value.Next(min, max);
}
public static int GetRandom(int max)
{
return RndLocal.Value.Next(max);
}
public static double GetRandom()
{
return RndLocal.Value.NextDouble();
}
}
public class StringUtility
{
private const string UpperAlpha = "ABCDEFGHIJKLMNOPQRSTUWXYZ";
private const string LowerAlpha = "abcdefghijklmnopqrstuwxyz";
private const string Numbers = "0123456789";
private const string SpecialChars = "~!##$%^&*()_-+=.?";
private static string CreateSourceString(bool includeLowerCase, bool includeUpperCase, bool includenumbers, bool includeSpChars)
{
Contract.Assert(includeLowerCase || includeUpperCase || includenumbers || includeSpChars);
var sb = new StringBuilder();
if (includeLowerCase) sb.Append(LowerAlpha);
if (includeUpperCase) sb.Append(UpperAlpha);
if (includenumbers) sb.Append(Numbers);
if (includeSpChars) sb.Append(SpecialChars);
return sb.ToString();
}
private static string GenerateString(string sourceString, int length = 6)
{
var rndString = Shuffle(sourceString);
var builder = new StringBuilder();
for (var i = 0; i < length; i++)
builder.Append(rndString[RandomUtils.GetRandom(0, rndString.Length)]);
return builder.ToString();
}
public static string GenerateRandomString(int length = 6,
bool includenumbers = false,
bool includeSpChars = false)
{
var sourceStr = CreateSourceString(true, true, includenumbers, includeSpChars);
return GenerateString(sourceStr, length);
}
public static string GenerateRandomString(int minLength,
int maxLength,
bool includenumbers = false,
bool includeSpChars = false)
{
if (maxLength < minLength) maxLength = minLength;
var len = RandomUtils.GetRandom(minLength, maxLength + 1);
return GenerateRandomString(len, includenumbers, includeSpChars);
}
public static string Shuffle(string str)
{
var alreadySwaped = new HashSet<Tuple<int, int>>();
var rndLoopCount = RandomUtils.GetRandom(Convert.ToInt32(str.Length / 4), Convert.ToInt32((str.Length / 2) + 1));
var strArray = str.ToArray();
for (var i = 0; i <= rndLoopCount; i++)
{
int rndIndex1 = 0, rndIndex2 = 0;
do
{
rndIndex1 = RandomUtils.GetRandom(0, str.Length);
rndIndex2 = RandomUtils.GetRandom(0, str.Length);
} while (alreadySwaped.Contains(new Tuple<int, int>(rndIndex1, rndIndex2)));
alreadySwaped.Add(new Tuple<int, int>(rndIndex1, rndIndex2));
var swappingChar = strArray[rndIndex1];
strArray[rndIndex1] = strArray[rndIndex2];
strArray[rndIndex2] = swappingChar;
}
return new string(strArray);
}
public static string GeneratePassword(PasswordComplexity complexityLevel)
{
switch (complexityLevel)
{
case PasswordComplexity.Simple: return GenerateSimplePassword();
case PasswordComplexity.Medium: return GenerateMediumPassword();
case PasswordComplexity.Strong: return GenerateStrongPassword();
case PasswordComplexity.Stronger: return GenerateStrongerPassword();
}
return null;
}
private static string GenerateSimplePassword()
{
return GenerateRandomString(6, 9);
}
private static string GenerateMediumPassword()
{
var passLen = RandomUtils.GetRandom(6, 10);
var numCount = RandomUtils.GetRandom(1, 3);
var alphaStr = GenerateRandomString(passLen - numCount);
var numStr = GenerateString(Numbers, numCount);
var pass = alphaStr + numStr;
return Shuffle(pass);
}
private static string GenerateStrongPassword()
{
var lowerCharCount = RandomUtils.GetRandom(2, 5);
var upperCharCount = RandomUtils.GetRandom(2, 5);
var numCount = RandomUtils.GetRandom(2, 4);
var spCharCount = RandomUtils.GetRandom(2, 4);
var lowerAlphaStr = GenerateString(LowerAlpha, lowerCharCount);
var upperAlphaStr = GenerateString(UpperAlpha, upperCharCount);
var spCharStr = GenerateString(SpecialChars, spCharCount);
var numStr = GenerateString(Numbers, numCount);
var pass = lowerAlphaStr + upperAlphaStr + spCharStr + numStr;
return Shuffle(pass);
}
private static string GenerateStrongerPassword()
{
var lowerCharCount = RandomUtils.GetRandom(5, 12);
var upperCharCount = RandomUtils.GetRandom(4, 8);
var numCount = RandomUtils.GetRandom(4, 6);
var spCharCount = RandomUtils.GetRandom(4, 6);
var lowerAlphaStr = GenerateString(LowerAlpha, lowerCharCount);
var upperAlphaStr = GenerateString(UpperAlpha, upperCharCount);
var spCharStr = GenerateString(SpecialChars, spCharCount);
var numStr = GenerateString(Numbers, numCount);
var pass = lowerAlphaStr + upperAlphaStr + spCharStr + numStr;
return Shuffle(Shuffle(pass));
}
public enum PasswordComplexity
{
Simple, Medium, Strong, Stronger
}
}

I write this code for you. You can just copy and use it. All of my code is just a method that you can pass appropriate arguments and it gives you back a completely randomized password. I test it several times before answering your question, It works well.
private string GeneratePassword(bool useCapitalLetters, bool useSmallLetters, bool useNumbers, bool useSymbols, int passLenght)
{
Random random = new Random();
StringBuilder password = new StringBuilder(string.Empty);
//This for loop is for selecting password chars in order
for (int i = 0;;)
{
if (useCapitalLetters)
{
password.Append((char)random.Next(65, 91)); //Capital letters
++i; if (i >= passLenght) break;
}
if (useSmallLetters)
{
password.Append((char)random.Next(97, 122)); //Small letters
++i; if (i >= passLenght) break;
}
if (useNumbers)
{
password.Append((char)random.Next(48, 57)); //Number letters
++i; if (i >= passLenght) break;
}
if (useSymbols)
{
password.Append((char)random.Next(35, 38)); //Symbol letters
++i; if (i >= passLenght) break;
}
}
//This for loop is for disordering password characters
for (int i = 0; i < password.Length; ++i)
{
int randomIndex1 = random.Next(password.Length);
int randomIndex2 = random.Next(password.Length);
char temp = password[randomIndex1];
password[randomIndex1] = password[randomIndex2];
password[randomIndex2] = temp;
}
return password.ToString();
}

an answer with complete randomize char and using the max repeat of char, i have added a shuffle string function:
const int Maximum_Identical = 2; // Max number of identical characters in a row
const string lower_chars = "abcdefghijklmnopqrstuvwxyz"; // lower case chars
const string capital_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //capital chars
const string numbers = "0123456789"; //numbers
const string symbols = #"!#$%&*#\"; //symbols
int lenght = 6; //
bool lowercase = true, capital=true, num=true, sym=true;
List<char[]> PasswordSet = new List<char[]>();
List<char[]> charSet = new List<char[]>();
List<int[]> countSet = new List<int[]>();
if (lowercase) charSet.Add(lower_chars.ToArray());
if (capital) charSet.Add(capital_chars.ToArray());
if (num) charSet.Add(numbers.ToArray());
if (sym) charSet.Add(symbols.ToArray());
foreach(var c in charSet)
countSet.Add(new int[c.Length]);
Random rdm = new Random();
//we create alist with each type with a length char (max repeat char included)
for(int i = 0; i < charSet.Count;i++)
{
var lng = 1;
var p0 = "";
while (true)
{
var ind = rdm.Next(0, charSet[i].Length);
if (countSet[i][ind] < Maximum_Identical )
{
countSet[i][ind] += 1;
lng++;
p0 += charSet[i][ind];
}
if (lng == lenght) break;
}
PasswordSet.Add(p0.ToArray());
}
//generate a password with the desired length with at less one char in desired type,
//and we choose randomly in desired type to complete the length of password
var password = "";
for(int i = 0; i < lenght; i++)
{
char p;
if (i < PasswordSet.Count)
{
int id;
do
{
id = rdm.Next(0, PasswordSet[i].Length);
p = PasswordSet[i][id];
} while (p == '\0');
password += p;
PasswordSet[i][id] = '\0';
}
else
{
int id0;
int id1;
do
{
id0 = rdm.Next(0, PasswordSet.Count);
id1 = rdm.Next(0, PasswordSet[id0].Length);
p = PasswordSet[id0][id1];
} while (p == '\0');
password += p;
PasswordSet[id0][id1] = '\0';
}
}
//you could shuffle the final password
password = Shuffle.StringMixer(password);
shuffle string function:
static class Shuffle
{
static System.Random rnd = new System.Random();
static void Fisher_Yates(int[] array)
{
int arraysize = array.Length;
int random;
int temp;
for (int i = 0; i < arraysize; i++)
{
random = i + (int)(rnd.NextDouble() * (arraysize - i));
temp = array[random];
array[random] = array[i];
array[i] = temp;
}
}
public static string StringMixer(string s)
{
string output = "";
int arraysize = s.Length;
int[] randomArray = new int[arraysize];
for (int i = 0; i < arraysize; i++)
{
randomArray[i] = i;
}
Fisher_Yates(randomArray);
for (int i = 0; i < arraysize; i++)
{
output += s[randomArray[i]];
}
return output;
}
}

There you go :
string[] charList =
{
"abcdefghijklmnopqrstuvwxyz",
"ABCDEFGHIJKLMNOPQRSTUVWXYZ",
"0123456789",
"#\"!#$%&*#\\"
};
int desiredPasswordLength = 12;
var randomNumberGenerator = new Random();
string generatedPassword = "";
for (int i = randomNumberGenerator.Next() % 4; desiredPasswordLength > 0; i = (i+1) % 4)
{
var takeRandomChars = randomNumberGenerator.Next() % 3;
for (int j = 0; j < takeRandomChars; j++)
{
var randomChar = randomNumberGenerator.Next() % charList[i].Length;
char selectedChar = charList[i][randomChar % charList[i].Length];
generatedPassword = string.Join("", generatedPassword, selectedChar);
}
desiredPasswordLength -= takeRandomChars;
}
Console.WriteLine("Generated password: {0}",generatedPassword);

private static string GeneratorPassword(UInt16 length = 8)
{
const string chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0";
System.Text.StringBuilder sb = new System.Text.StringBuilder();
Random rnd = new Random();
System.Threading.Thread.Sleep(2);
for (int i = 0; i < length; i++)
{
int index = 0;
if (i % 3 == 0)
{
index = rnd.Next(0, 10);
}
else if (i % 3 == 1)
{
index = rnd.Next(10, 36);
}
else
{
index = rnd.Next(36, 62);
}
sb.Insert(rnd.Next(0, sb.Length), chars[index].ToString());
}
return sb.ToString();
}
static void Main(string[] args)
{
for (int j= 0; j < 100; j++)
{
Console.WriteLine( GeneratorPassword());
}
Console.ReadLine();
}

i want to generate alfa numeric otp in asp.net c#

public void generate()
{
string alphabets = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string small_alphabets = "abcdefghijklmnopqrstuvwxyz";
string numbers = "1234567890";
string characters = numbers;
characters += alphabets + small_alphabets + numbers;
int length =6;
string opt = string.Empty;
for (int i = 0; i < length; i++)
{
string character = string.Empty;
do
{
int index = new Random().Next(0, characters.Length);
character = characters.ToCharArray()[index].ToString();
} while (otp.IndexOf(character) != -1);
otp += character;
}
string str= otp;
}
This is my code, which is not working for me.
I want to try small alphabet, capital alphabet and 0 to 9 number combination.

Here is the code :
var chars1 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
var stringChars1 = new char[6];
var random1 = new Random();
for (int i = 0; i < stringChars1.Length; i++)
{
stringChars1[i] = chars1[random1.Next(chars1.Length)];
}
var str= new String(stringChars1);

This code will give you numeric otp of n digits.
public static int GenerateOTP(int digits)
{
if (digits < 3)
return new Random().Next(10, 99);
else
return new Random().Next(MultiplyNTimes(digits), MultiplyNTimes(digits + 1) - 1);
}
private static int MultiplyNTimes(int n)
{
if (n == 1)
return 1;
else
return 10 * MultiplyNTimes(n - 1);
}

How do I generate a random alphanumeric array that has 3 letter and 6 digits in c#?

I am trying to generate a random alphanumeric array that consist of 3 letters and 6 digits. The entire array must be random. The only way I could think of is generating 2 individual random arrays and then merging them and randomizing the merged array. Any help would be appreciated. I specifically need help on ensuring that the correct number of variable types are stored. Here is my semi-working code:
static void Main(string[] args)
{
var alphabetic = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var numeric = "0123456789";
var stringChars = new char[9];
var random = new Random();
for (int i = 0; i < 3; i++)
{
stringChars[i] = alphabetic[random.Next(alphabetic.Length)];
}
for(int i = 3; i< stringChars.Length; i++)
{
stringChars[i] = numeric[random.Next(numeric.Length)];
}
var ranChars = new char[9];
var semisorted = new String(stringChars);
for (int i=0; i< ranChars.Length; i++)
{
ranChars[i] = semisorted[random.Next(semisorted.Length)];
}
var final = new string(ranChars);
Console.WriteLine("{0}", final);
Console.ReadLine();
}

You're close. But the problem here is that you're selecting randomly from the "semi-sorted" array, while what's really necessary at that point is picking a random permutation. One way to do that is with a Fisher-Yates shuffle.
So combining that with the code you had that worked: (not tested)
for (int i = 0; i < 3; i++)
{
stringChars[i] = alphabetic[random.Next(alphabetic.Length)];
}
for(int i = 3; i< stringChars.Length; i++)
{
stringChars[i] = numeric[random.Next(numeric.Length)];
}
int n = stringChars.Length;
while (n > 1)
{
int k = random.Next(n--);
char temp = stringChars[n];
stringChars[n] = stringChars[k];
stringChars[k] = temp;
}
string result = new string(stringChars);

Harold's answer is way cleaner, but here's another approach for the whole '100 ways to do the same thing in programming' concept. [Edit: Doh, I reversed the number of digits and letters. Here's a fix:]
public static void Main(string[] args)
{
var random = new Random();
var finalString = string.Empty;
var finalArray = new string[9];
for (var i = 0; i < 3; i++)
{
var alphabet = random.Next(0, 26);
var letter = (char) ('a' + alphabet);
finalArray[i] = letter.ToString().ToUpper();
}
for (var i = 3; i < 9; i++)
{
var number = random.Next(0, 9);
finalArray[i] = number.ToString();
}
var shuffleArray = finalArray.OrderBy(x => random.Next()).ToArray();
for (var i = 0; i < finalArray.Length; i++)
{
finalString += shuffleArray[i];
}
Console.WriteLine(finalString);
Console.ReadKey();
}

csharp method that choose every second character from the word

I need a method that returns every other character in a string starting with the first character. For example, a method call with ("Java-language") returns "Jv-agae."
private static void NewMethod(string word)
{
// here comes the code
}

var str = "Java-language";
var xx = new string(str.Where((ch, index) => index % 2 == 0).ToArray());
Console.WriteLine(xx);
Or this one:
var xx = string.Join<char>("", str.Where((ch, index) => (index & 1) == 0));

probably little different then everybody else: :-)
protected static IEnumerable<char> EverySecondChar(string word)
{
for(int i = 0; i < word.Length; i += 2)
yield return word[i];
}
string result = new string(EverySecondChar("Java-language").ToArray());

Here is my suggestion for you:
private string TakeEverySecondChar(string input)
{
var result = string.Empty;
for (int i = 0; i < input.Length; i+=2)
{
result += input.Substring(i, 1);
}
return result;
}

Console.Clear();
string Lang = "Java-language";
string[] LangArr = new string[Lang.Length];
char LangChar;
for (int i = 0; i < Lang.Length; i++)
{
LangChar = Lang[i];
LangArr[i] = LangChar.ToString();
}
for (int i = 0; i < LangArr.Length; i++)
{
Console.Write(LangArr[i]);
i++;
}
Console.ReadLine();

public String strip2ndchar(string text)
{
string final="";
int i = 0;
foreach (char a in text.ToCharArray())
{
if (i % 2 == 0)
final += a;
i++;
}
return final;
}

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