Program for length of a string using recursion

Given a string calculate length of the string using recursion.

Examples:

Input : str = "abcd"
Output :4

Input : str = "GEEKSFORGEEKS"
Output :13

We have discussed 5 Different methods to find length of a string in C++
How to find length of a string without string.h and loop in C?

Algorithm

recLen(str)
{
   If str is NULL 
       return 0
   Else 
      return 1 + recLen(str + 1)
}

C++

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// CPP program to calculate length of 
// a string using recursion
#include <bits/stdc++.h>
using namespace std;
  
/* Function to calculate length */
int recLen(char* str)    
{
    // if we reach at the end of the string
    if (*str == '\0'
        return 0;
    else
        return 1 + recLen(str + 1); 
}
  
/* Driver program to test above function */
int main()
{
    char str[] = "GeeksforGeeks";
    cout << recLen(str);
    return 0;
}

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Java

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// java program to calculate length of 
// a string using recursion
import java.util.*;
  
public class GFG{
  
    /* Function to calculate length */
    private static int recLen(String str) 
    {
  
        // if we reach at the end of the string
        if (str.equals(""))
            return 0;
        else
            return recLen(str.substring(1)) + 1;
    }
  
    /* Driver program to test above function */
    public static void main(String[] args) 
    {
  
          
        String str ="GeeksforGeeks";
        System.out.println(recLen(str));
    }
}
  
// This code is contributed by Sam007.

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Python3

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# Python program to calculate 
# length of a string using 
# recursion
str = "GeeksforGeeks"
  
# Function to 
# calculate length
def recLen(i) :
  
    global str
      
    # if we reach at the
    # end of the string
    if (i == len(str)) :
        return 0
    else :
        return 1 + recLen(i + 1
      
# Driver Code
print (recLen(0))
  
# This code is contributed by
# Manish Shaw(manishshaw1)

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C#

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// C# program to calculate length of 
// a string using recursion
using System;
  
public class GFG{
  
    /* Function to calculate length */
    private static int recLen(string str) 
    {
  
        // if we reach at the end of the string
        if (str.Equals(""))
            return 0;
        else
            return recLen(str.Substring(1)) + 1;
    }
  
    /* Driver program to test above function */
    public static void Main() 
    {
  
          
        string str ="GeeksforGeeks";
        Console.WriteLine(recLen(str));
    }
}
  
// This code is contributed by vt_m.

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PHP

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<?php
// PHP program to calculate 
// length of a string using 
// recursion
   
// Function to 
// calculate length
function recLen(&$str, $i)    
{
    // if we reach at the
    // end of the string
    if ($i == strlen($str)) 
        return 0;
    else
        return 1 + 
               recLen($str
                      $i + 1); 
}
    
// Driver Code
$str = "GeeksforGeeks";
echo (recLen($str, 0));
  
// This code is contributed by
// Manish Shaw(manishshaw1)
?>

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Output:

13

Time Complexity : O(n)
Auxiliary Space : O(n) for recursion call stack.

Since this solution requires extra space and function call overhead, it is not recommended to use it in practice.



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Improved By : manishshaw1



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