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JS decryption method translate to C#

I need some help with JS code translation to C#.
JS Code:
function Decription(string) {
var newString = '',
char, codeStr, firstCharCode, lastCharCode;
var ft = escape(string);
string = decodeURIComponent(ft);
for (var i = 0; i < string.length; i++) {
char = string.charCodeAt(i);
if (char > 132) {
codeStr = char.toString(10);
firstCharCode = parseInt(codeStr.substring(0, codeStr.length - 2), 10);
lastCharCode = parseInt(codeStr.substring(codeStr.length - 2, codeStr.length), 10) + 31;
newString += String.fromCharCode(firstCharCode) + String.fromCharCode(lastCharCode);
} else {
newString += string.charAt(i);
}
}
return newString;
}
And I tied to translate on C#:
private string Decription(string encriptedText)
{
string ft = Regex.Escape(encriptedText);
string text = HttpUtility.UrlDecode(ft);
string newString = "";
for (int i = 0; i < text.Length; i++)
{
var ch = (int)text[i];
if(ch > 132)
{
var codeStr = Convert.ToString(ch, 10);
var firstCharCode = Convert.ToInt32(codeStr.Substring(0, codeStr.Length - 2), 10);
var lastCharCode = Convert.ToInt32(codeStr.Substring(codeStr.Length - 2, codeStr.Length), 10) + 31;
}
}
}
But how I can translate this row:
newString += String.fromCharCode(firstCharCode) + String.fromCharCode(lastCharCode);
Maybe do you know equivalent method to String.fromCharCode() on C# ?

Here you go:
public static void Main()
{
// from 97 to a
int i = 97;
Console.WriteLine(StringFromCharCode(97));
}
public static string StringFromCharCode(int code) => ((char)code).ToString();
Demo
Note that you may want to use a StringBuilder instead of concatening string in your case.
Related to Int to Char in C# (Read it. It includes a nice comment about cast vs Convert.ToChar)

You can simply use Convert.ToChar method, Convert.ToChar(97) will return a.

Decode GSM 7 bit in C#

I need to decode GSM 7 bit to ascii string in c# so that I googled and found lots of different posts about it, this post is one of them but It is not a c#.
Can anyone please share a c# code that can decode GSM 7-bit Character to ASCII string.
Thanks.

class GSM7BitDecoder
{
// Basic Character Set
private const string BASIC_SET =
"#£$¥èéùìòÇ\nØø\rÅåΔ_ΦΓΛΩΠΨΣΘΞ\x1bÆæßÉ !\"#¤%&'()*+,-./0123456789:;<=>?" +
"¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑܧ¿abcdefghijklmnopqrstuvwxyzäöñüà";
// Basic Character Set Extension
private const string EXTENSION_SET =
"````````````````````^```````````````````{}`````\\````````````[~]`" +
"|````````````````````````````````````€``````````````````````````";
string[] BASIC_SET_ARRAY = BASIC_SET.Select(x => x.ToString()).ToArray();
string[] EXTENSION_SET_ARRAY = EXTENSION_SET.Select(x => x.ToString()).ToArray();
enum circle { Start=1, Complete=8 }
string GetChar(string bin)
{
try
{
if (Convert.ToInt32(bin, 2).Equals(27))
return EXTENSION_SET_ARRAY[Convert.ToInt32(bin, 2)];
else
return BASIC_SET_ARRAY[Convert.ToInt32(bin, 2)];
}
catch { return string.Empty; }
}
public string DecodeGSM7bit(string strGsm7bit)
{
var suffix = string.Empty;
var septet = string.Empty;
var CurSubstr = string.Empty;
var counter = 1;
List<string> septets = new List<string>();
List<string> sectets = new List<string>();
//Prepare Octets
var octets = Enumerable.Range(0, strGsm7bit.Length / 2).Select(i =>
{
return Convert.ToString(Convert.ToInt64(strGsm7bit.Substring(i * 2, 2), 16), 2).PadLeft(8,'0');
}).ToList();
for (var index=0; index < octets.Count; index = index +1)
{
//Generate Septets
septet = octets[index].Substring(counter);
CurSubstr = octets[index].Substring(0, counter);
if (counter.Equals((int)circle.Start))
septets.Add(septet);
else
septets.Add(septet + suffix);
//Organize Sectets
sectets.Add(GetChar(septets[index]));
suffix = CurSubstr;
counter++;
//Reset counter when the circle is complete.
if (counter == (int)circle.Complete)
{
counter = (int)circle.Start;
sectets.Add(GetChar(suffix));
}
}
return string.Join("", sectets);
}

How to cast an 'int' to a 'char' in C#?

I have a string variable which has a mixture of numbers and letters. I want to create a new string that only has int values of the previous string variable. So I found two ways to cast int to char. However, they do not work. Here's what I've tried
string onlyNumberString = "";
foreach (char onlyNum in puzzleData)
{
for (int i = 1; i < 10; i++)
{
if (onlyNum == (char)i)
{
onlyNumberString += onlyNum;
}
}
}
and
string onlyNumberString = "";
foreach (char onlyNum in puzzleData)
{
for (int i = 1; i < 10; i++)
{
if (onlyNum == Convert.ToChar(i))
{
onlyNumberString += onlyNum;
}
}
}

Use Char.IsDigit instead, far simpler.
StringBuilder onlyNumber = new StringBuilder();
foreach (char onlyNum in puzzleData)
{
if (Char.IsDigit(onlyNum))
{
onlyNumber.Append(onlyNum);
}
}

int iNum = 2;
char cChar = iNum.ToString()[0];
Will work for x when 0 <= x <= 9.

You can just cast an int to a char it directly:
var myChar = (char)20;
But to do what you want I suggest using a regular expression:
var onlyNumerals = Regex.Replace(myString, #"[^0-9]", "");
The above will replace any character that is not 0-9 with an empty space.
An alternative, using LINQ and char.IsDigit:
var onlyNumeral = new string(myString.Where(c => Char.IsDigit(c)).ToArray());

You can do it as:
string justNumbers = new String(text.Where(Char.IsDigit).ToArray());

A few ways:
(char)int
Or
int.Parse(char.ToString())
Or
Convert.ToChar(int);

Appending Strings in Java/C# without using StringBuffer.Append or StringBuilder.Append

at a recent interview I attended, the programming question that was asked was this. Write a function that will take as input two strings. The output should be the result of concatenation.
Conditions: Should not use StringBuffer.Append or StringBuilder.Append or string objects for concatenation;that is, they want me to implement the pseudo code implementation of How StringBuilder or StringBuffer's Append function works.
This is what I did:
static char[] AppendStrings(string input, string append)
{
char[] inputCharArray = input.ToCharArray();
char[] appendCharArray = append.ToCharArray();
char[] outputCharArray = new char[inputCharArray.Length + appendCharArray.Length];
for (int i = 0; i < inputCharArray.Length; i++)
{
outputCharArray[i] = inputCharArray[i];
}
for (int i = 0; i < appendCharArray.Length; i++)
{
outputCharArray[input.Length + i] = appendCharArray[i];
}
return outputCharArray;
}
While this is a working solution, is there a better way of doing things?

is LINQ legal? strings are just can be treated as an enumeration of chars, so they can be used with LINQ (even though there is some cost involved, see comments):
string a = "foo";
string b = "bar";
string c = new string(a.AsEnumerable().Concat(b).ToArray());
or with your method signature:
static char[] AppendStrings(string input, string append)
{
return input.AsEnumerable().Concat(append).ToArray();
}

You can call CopyTo:
char[] output = new char[a.Length + b.Length];
a.CopyTo(0, output, 0, a.Length);
b.CopyTo(0, output, a.Length, b.Length);
return new String(output);
If they don't like that, call .ToCharArray().CopyTo(...).
You can also cheat:
return String.Join("", new [] { a, b });
return String.Format("{0}{1}", a, b);
var writer = new StringWriter();
writer.Write(a);
writer.Write(b);
return writer.ToString();

I would've done something like the following (argument checking omitted for brevity)
public static string Append(string left, string right) {
var array = new char[left.Length + right.Length];
for (var i = 0; i < left.Length; i++) {
array[i] = left[i];
}
for (var i = 0; i < right.Length; i++) {
array[i + left.Length] = right[i];
}
return new string(array);
}

In Java you can just use concat which does not use StringBuilder or StringBuffer.
String a = "foo";
String b = "bar";
String ab = a.concat(b);
The source for String.concat(String) from Oracle's JDK.
public String concat(String str) {
int otherLen = str.length();
if (otherLen == 0) {
return this;
}
char buf[] = new char[count + otherLen];
getChars(0, count, buf, 0);
str.getChars(0, otherLen, buf, count);
return new String(0, count + otherLen, buf);
}

java default support "+" for append string
String temp="some text";
for(int i=0;i<10;i++)
{
temp=temp+i;
}
Or
temp=temp+" some other text"

How to extract phrases and then words in a string of text?

I have a search method that takes in a user-entered string, splits it at each space character and then proceeds to find matches based on the list of separated terms:
string[] terms = searchTerms.ToLower().Trim().Split( ' ' );
Now I have been given a further requirement: to be able to search for phrases via double quote delimiters a la Google. So if the search terms provided were:
"a line of" text
The search would match occurrences of "a line of" and "text" rather than the four separate terms [the open and closing double quotes would also need to be removed before searching].
How can I achieve this in C#? I would assume regular expressions would be the way to go, but haven't dabbled in them much so don't know if they are the best solution.
If you need any more info, please ask. Thanks in advance for the help.

Here's a regex pattern that would return matches in groups named 'term':
("(?<term>[^"]+)"\s*|(?<term>[^ ]+)\s*)+
So for the input:
"a line" of text
The output items identified by the 'term' group would be:
a line
of
text

Regular expressions would definitely be the way to go...
You should check this MSDN link out for some info on the Regex class:
http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex.aspx
and here is an excellent link to learn some regular expression syntax:
http://www.radsoftware.com.au/articles/regexlearnsyntax.aspx
Then to add some code examples, you could be doing it something along these lines:
string searchString = "a line of";
Match m = Regex.Match(textToSearch, searchString);
or if you just want to find out if the string contains a match or not:
bool success = Regex.Match(textToSearch, searchString).Success;

use the regular expression builder here
http://gskinner.com/RegExr/
and you will be able to manipulate the regular expression to how you need it displayed

Use Regexs....
string textToSearchIn = ""a line of" text";
string result = Regex.Match(textToSearchIn, "(?<=").*?(?=")").Value;
or if more then one, put this into a match collection...
MatchCollection allPhrases = Regex.Matches(textToSearchIn, "(?<=").*?(?=")");

The Knuth-Morris-Pratt (KMP algorithm)is recognised as the fastest algorithm for finding substrings in strings (well, technically not strings but byte-arrays).
using System.Collections.Generic;
namespace KMPSearch
{
public class KMPSearch
{
public static int NORESULT = -1;
private string _needle;
private string _haystack;
private int[] _jumpTable;
public KMPSearch(string haystack, string needle)
{
Haystack = haystack;
Needle = needle;
}
public void ComputeJumpTable()
{
//Fix if we are looking for just one character...
if (Needle.Length == 1)
{
JumpTable = new int[1] { -1 };
}
else
{
int needleLength = Needle.Length;
int i = 2;
int k = 0;
JumpTable = new int[needleLength];
JumpTable[0] = -1;
JumpTable[1] = 0;
while (i <= needleLength)
{
if (i == needleLength)
{
JumpTable[needleLength - 1] = k;
}
else if (Needle[k] == Needle[i])
{
k++;
JumpTable[i] = k;
}
else if (k > 0)
{
JumpTable[i - 1] = k;
k = 0;
}
i++;
}
}
}
public int[] MatchAll()
{
List<int> matches = new List<int>();
int offset = 0;
int needleLength = Needle.Length;
int m = Match(offset);
while (m != NORESULT)
{
matches.Add(m);
offset = m + needleLength;
m = Match(offset);
}
return matches.ToArray();
}
public int Match()
{
return Match(0);
}
public int Match(int offset)
{
ComputeJumpTable();
int haystackLength = Haystack.Length;
int needleLength = Needle.Length;
if ((offset >= haystackLength) || (needleLength > ( haystackLength - offset)))
return NORESULT;
int haystackIndex = offset;
int needleIndex = 0;
while (haystackIndex < haystackLength)
{
if (needleIndex >= needleLength)
return haystackIndex;
if (haystackIndex + needleIndex >= haystackLength)
return NORESULT;
if (Haystack[haystackIndex + needleIndex] == Needle[needleIndex])
{
needleIndex++;
}
else
{
//Naive solution
haystackIndex += needleIndex;
//Go back
if (needleIndex > 1)
{
//Index of the last matching character is needleIndex - 1!
haystackIndex -= JumpTable[needleIndex - 1];
needleIndex = JumpTable[needleIndex - 1];
}
else
haystackIndex -= JumpTable[needleIndex];
}
}
return NORESULT;
}
public string Needle
{
get { return _needle; }
set { _needle = value; }
}
public string Haystack
{
get { return _haystack; }
set { _haystack = value; }
}
public int[] JumpTable
{
get { return _jumpTable; }
set { _jumpTable = value; }
}
}
}
Usage :-
using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
namespace KMPSearch
{
class Program
{
static void Main(string[] args)
{
if (args.Length != 2)
{
Console.WriteLine("Usage: " + Environment.GetCommandLineArgs()[0] + " haystack needle");
}
else
{
KMPSearch search = new KMPSearch(args[0], args[1]);
int[] matches = search.MatchAll();
foreach (int i in matches)
Console.WriteLine("Match found at position " + i+1);
}
}
}
}

Try this, It'll return an array for text. ex: { "a line of" text "notepad" }:
string textToSearch = "\"a line of\" text \" notepad\"";
MatchCollection allPhrases = Regex.Matches(textToSearch, "(?<=\").*?(?=\")");
var RegArray = allPhrases.Cast<Match>().ToArray();
output: {"a line of","text"," notepad" }