I've just had to write a string reverse function in C# 2.0 (i.e. LINQ not available) and came up with this:
public string Reverse(string text)
{
char[] cArray = text.ToCharArray();
string reverse = String.Empty;
for (int i = cArray.Length - 1; i > -1; i--)
{
reverse += cArray[i];
}
return reverse;
}
Personally I'm not crazy about the function and am convinced that there's a better way to do it. Is there?
Have a look at the wikipedia entry here. They implement the String.Reverse extension method. This allows you to write code like this:
string s = "olleh";
s.Reverse();
They also use the ToCharArray/Reverse combination that other answers to this question suggest. The source code looks like this:
public static string Reverse(this string input)
{
char[] chars = input.ToCharArray();
Array.Reverse(chars);
return new String(chars);
}
Sorry for long post, but this might be interesting
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
public static string ReverseUsingArrayClass(string text)
{
char[] chars = text.ToCharArray();
Array.Reverse(chars);
return new string(chars);
}
public static string ReverseUsingCharacterBuffer(string text)
{
char[] charArray = new char[text.Length];
int inputStrLength = text.Length - 1;
for (int idx = 0; idx <= inputStrLength; idx++)
{
charArray[idx] = text[inputStrLength - idx];
}
return new string(charArray);
}
public static string ReverseUsingStringBuilder(string text)
{
if (string.IsNullOrEmpty(text))
{
return text;
}
StringBuilder builder = new StringBuilder(text.Length);
for (int i = text.Length - 1; i >= 0; i--)
{
builder.Append(text[i]);
}
return builder.ToString();
}
private static string ReverseUsingStack(string input)
{
Stack<char> resultStack = new Stack<char>();
foreach (char c in input)
{
resultStack.Push(c);
}
StringBuilder sb = new StringBuilder();
while (resultStack.Count > 0)
{
sb.Append(resultStack.Pop());
}
return sb.ToString();
}
public static string ReverseUsingXOR(string text)
{
char[] charArray = text.ToCharArray();
int length = text.Length - 1;
for (int i = 0; i < length; i++, length--)
{
charArray[i] ^= charArray[length]