How can we find length of a string without the help of length method of string

Question

How can we find length of a string without the help of length method of string in C# ?

Answer 1

Here's a rather crude way to do it:

using System;

class Test

{

   static void Main()

   {

       string s = "Shubham";

       int length = 0;

       try

       {

          char c;

          while(true)

          {

             c = s[length];

             length++;

          }

       }

       catch(IndexOutOfRangeException)

       {

       }

       Console.WriteLine("The length of '{0}' is {1}", s, length);

       Console.ReadKey();

   }

}

A more elegant way would be to use pointers but, as you wouldn't even be asking the question if you knew about these, then I won't elaborate further.

Answer 2

Sure, here it is:

using System;

class Test

{

   unsafe static void Main()

   {

       string s = "Shubham";

       int length = 0;

       fixed(char* ps = s)

       {

          char* pc = ps;

          while(*pc++ != '\0') length++;

       } 

       Console.WriteLine("The length of '{0}' is {1}", s, length);

       Console.ReadKey();

   }

}

You'll need to compile with the /unsafe switch.

This works because, although you're not normally aware of it, all strings in .NET are stored in memory with a terminating null character '\0'. So, all you need to do is to keep incrementing the pointer until the null character is reached.

Notice though that, if the string actually contains a null character, then this approach will give an answer which is too small. The 'crude' method doesn't suffer from this problem.

Answer 3

Hi Vulpes, Give me the second way to get the length of string using pointer.