i want to generate alfa numeric otp in asp.net c# - 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);
}

Related

c# split string by random length

lets say i have an string like the below:
AAAABBBBBBBBBBCCCC
Currently my code can only split the above string equally by the len that I use as parameter using the function below:
private static IEnumerable<string> SplitByLength(string str, int maxLength)
{
for (var index = 0; index < str.Length; index += maxLength)
yield return str.Substring(index, Math.Min(maxLength, str.Length - index));
}
but this isnt what i want, I want the string to be splitted to random len, lets say between 2 to 10 char. example:
AAA
ABBBBB
BB
BBBCCC
C
the split len should be random. any hints how can I make it?
Check this:
private static IEnumerable<string> SplitByLength(string str, int maxLength)
{
var random = new Random();
var count = Math.Min(random.Next(1, maxLength + 1), str.Length);
int index = 0;
while (index < str.Length)
{
yield return str.Substring(index, count);
index += count;
count = Math.Min(random.Next(1, maxLength + 1), str.Length - index);
}
}
This works.
private static List<string> SplitString(string input)
{
var result = new List<string>();
var tempString = input;
var testString = "";
while (true)
{
var maxInt = tempString.Length <= 35 ? tempString.Length : 35;
var minInt = tempString.Length <= 10 ? tempString.Length : 10;
var random1 = Random.Next(minInt, maxInt);
result.Add(tempString.Substring(0, random1));
testString += tempString.Substring(0, random1);
tempString = tempString.Remove(0, random1);
if (tempString.Length == 0)
{
break;
}
}
return result;
}

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();
}

How to generate a Alphanumeric sequence number in c#

I wrote below code for generating my 8 digit character number, increment should happen from left to right.
suppose my starting Number is ABC00001 the next increment number will be ABC00002
number will increment up to 9 and after 9 it will change to A .
eg: ABC00009 -- >ABC00000A --> ABC00000B --> .... -->ABC00000Z
after Z it will change last second digit number as ABC0000A1 --> ABC0000A2 ...
public static string GeneratedNextevcPrimakryKey()
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
string str = string.Empty;
var maxNumber = "ONC0BJKZ";
string splitnumber = maxNumber.Substring(3, 5);
char[] temp = splitnumber.ToCharArray();
//find last index number/character
for (int i = splitnumber.Length - 1; i >= 0; i--)
{
if (char.IsNumber(splitnumber[i]))
{
int fifthvalue = Convert.ToInt32(splitnumber[i].ToString());
//increment 5th digit character
if (fifthvalue == 9)
{
temp[i] = 'A';
break;
}
else
{
fifthvalue = fifthvalue + 1;
string f = Convert.ToString(fifthvalue);
temp[i] = Convert.ToChar(f);
//sb.Append(fifthvalue);
break;
}
}
else
{
char letter = splitnumber[i];
char nextChar = new char();
if (letter == 'z')
{
string strvalue = Convert.ToString(1);
temp[i] = Convert.ToChar(strvalue);
}
else if (letter == 'Z')
{
//last digit character
string strvalue = Convert.ToString(1);
temp[i] = Convert.ToChar(strvalue);
str = new string(temp);
break;
}
else
nextChar = (char)(((int)letter) + 1);
temp[i] = nextChar;
str = new string(temp);
break;
}
}
return str;
}
You can try to implement Base36
void Main()
{
// 17 would be the number you want to convert to your ABC format
var result = ToBase36(17);
Console.WriteLine(result);
// Will print "ABC00000H"
}
private static string ToBase36(ulong value)
{
const string base36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var sb = new StringBuilder(9);
do
{
sb.Insert(0, base36[(byte)(value % 36)]);
value /= 36;
} while (value != 0);
var paddedString = "ABC" + sb.ToString().PadLeft(6, '0');
return paddedString;
}

Removing Leading Zeros in a Char Array

I'm attempting to subtract two strings (of theoretically infinite length) without the use of libraries like BigIntbut I was wondering if anybody has any good ideas on how to remove the leading zeros in the corner cases like the one below?
static void Main(string[] args)
{
Console.WriteLine(Subtract("10", "10005"));
}
static string ReverseInput(string inputString)
{
char[] charArray = inputString.ToCharArray();
Array.Reverse(charArray);
return new string(charArray);
}
static string Subtract(string firstNumInput, string secondNumInput)
{
string firstNum = String.Empty;
string secondNum = String.Empty;
bool negative = false;
// Reverse order of string input
if (firstNumInput.Length > secondNumInput.Length)
{
firstNum = ReverseInput(firstNumInput);
secondNum = ReverseInput(secondNumInput);
}
else if (firstNumInput.Length < secondNumInput.Length)
{
negative = true;
firstNum = ReverseInput(secondNumInput);
secondNum = ReverseInput(firstNumInput);
}
else if (firstNumInput.Length == secondNumInput.Length)
{
// iterate through string to find largest
}
char[] result = new char[firstNum.Length + 1];
int resultLength = 0;
int carry = 0;
for (int i = 0; i < firstNum.Length; i++)
{
int an = (i < firstNum.Length) ? int.Parse(firstNum[i].ToString()) : 0;
int bn = (i < secondNum.Length) ? int.Parse(secondNum[i].ToString()) : 0;
int rn = an - bn - carry;
if (rn < 0)
{
carry = 1;
rn += 10;
}
else
{
carry = 0;
}
result[resultLength++] = (char)(rn + '0');
}
// create the result string from the char array
string finalResult = ReverseInput(new string(result, 0, resultLength));
if (negative)
{
finalResult = '-' + finalResult;
}
return finalResult;
}
Are you looking for TrimStart?
// create the result string from the char array
string finalResult = ReverseInput(new string(result, 0, resultLength)).TrimStart('0');

How do I insert characters into an alpha-numeric string

I'm new to C#. I have a short form and a long form of a client code. The short form is some alpha characters and some numeric ones (ABC12), while the long form is always 15 characters long with the space between the alpha and the numeric parts padded out with zeros (ABC000000000012). I need to be able to convert from the short form to the long. The code below is how I've got it to work - is this the best way to do this?
public string ExpandCode(string s)
{
// s = "ABC12"
int i = 0;
char c;
bool foundDigit = false;
string o = null;
while (foundDigit == false)
{
c = Convert.ToChar(s.Substring(i, 1));
if (Char.IsDigit(c))
{
foundDigit = true;
o = s.Substring(0, i) + new String('0', 15-s.Length) + s.Substring(i,s.Length-i);
}
i += 1;
}
return (o); //o = "ABC000000000012"
}
Your code is basically correct, however it could be slow, since String.Substring(...) creates a new string every time called.
I also suggest that you use the built-in functions of the .NET api for accomplishing your tasks, which can make coding easier a lot:
private char[] numbers = new char[]{'1', '2', '3', '4', '5', '6', '7', '8', '9', '0'};
public string ExpandCode(string s)
{
//Find the first numeric char.
int index = s.IndexOfAny(numbers);
//Insert zeros and return the result.
return s.Insert(index, new String('0', 15 - s.Length));
}
Take a look at this:
public string ExpandCode(string s)
{
var builder = new StringBuilder(s);
var index = Array.FindIndex(s.ToArray(), x => char.IsDigit(x));
while (builder.Length < 15)
{
builder.Insert(index, '0');
}
return builder.ToString();
}
I assume that string are always letter -> digit (like "abc123" or "ab1234").
The purer, the faster
public static string ExpandCode4(string s)
{
char[] res = new char[15];
int ind = 0;
for (int i = 0; i < s.Length && s[i] >= 'A'; i++)
res[ind++] = s[i];
int tillDigit = ind;
for (int i = 0; i < 15 - s.Length; i++)
res[ind++] = '0';
for (int i = 0; i < s.Length - tillDigit; i++)
res[ind++] = s[tillDigit + i];
return new string(res);
}
Benchmark for all the answers is as follows,
internal class Program
{
private static void Main(string[] args)
{
var inputs = new List<string>();
for (int i = 0; i < 10000000; i++)
{
inputs.Add("ABC1234");
}
var n1 = DateTime.Now;
inputs.ForEach(i => ExpandCode1(i));
var r1 = (DateTime.Now - n1).Ticks;
var n2 = DateTime.Now;
inputs.ForEach(i => ExpandCode2(i));
var r2 = (DateTime.Now - n2).Ticks;
var n3 = DateTime.Now;
inputs.ForEach(i => ExpandCode3(i));
var r3 = (DateTime.Now - n3).Ticks;
var n4 = DateTime.Now;
inputs.ForEach(i => ExpandCode4(i));
var r4 = (DateTime.Now - n4).Ticks;
var results = new List<Result>()
{
new Result() {Name = "1", Ticks = r1},
new Result() {Name = "2", Ticks = r2},
new Result() {Name = "3", Ticks = r3},
new Result() {Name = "4", Ticks = r4}
};
results.OrderBy(r => r.Ticks).ToList().ForEach(Console.WriteLine);
Console.ReadKey();
}
public static string ExpandCode4(string s)
{
char[] res = new char[15];
int ind = 0;
for (int i = 0; i < s.Length && s[i] >= 'A'; i++)
res[ind++] = s[i];
int tillDigit = ind;
for (int i = 0; i < 15 - s.Length; i++)
res[ind++] = '0';
for (int i = 0; i < s.Length - tillDigit; i++)
res[ind++] = s[tillDigit + i];
return new string(res);
}
public static string ExpandCode1(string s)
{
char[] numbers = new char[] { '1', '2', '3', '4', '5', '6', '7', '8', '9', '0' };
//Find the first numeric char.
int index = s.IndexOfAny(numbers);
//Insert zeros and return the result.
return s.Insert(index, new String('0', 15 - s.Length));
}
public static string ExpandCode2(string s)
{
var builder = new StringBuilder(s);
var index = Array.FindIndex(s.ToArray(), x => char.IsDigit(x));
while (builder.Length < 15)
{
builder.Insert(index, '0');
}
return builder.ToString();
}
public static string ExpandCode3(string s)
{
var match = Regex.Match(s, #"([^\d]+)(\d+)");
var letters = match.Groups[1].Value;
var numbers = int.Parse(match.Groups[2].Value);
var formatString = "{0}{1:d" + (15 - letters.Length) + "}";
var longForm = string.Format(formatString, letters, numbers);
return longForm;
}
}
public class Result
{
public long Ticks { get; set; }
public string Name { get; set; }
public override string ToString()
{
return Name + " - " + Ticks;
}
}
You can use string.Format() to take care of the padding for you. I used regex (and not in a very robust manner) to parse out the letters and numbers but you may be able to do this more efficiently another way.
The key point is that we dynamically figure out how many zero's we need, and then use a format string of the form X:dY where X = format ordinal and Y = the number of zeros you wish to pad.
var match = Regex.Match("ABC12", #"([^\d]+)(\d+)");
var letters = match.Groups[1].Value;
var numbers = int.Parse(match.Groups[2].Value);
var formatString = "{0}{1:d" + (15 - letters.Length) + "}";
var longForm = string.Format(formatString, letters, numbers);

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