Day 68: Python Program to Reverse a String using Recursion

 

def reverse_string(s):

    if len(s) <= 1:

        return s

     return reverse_string(s[1:]) + s[0]

input_string = input("Enter a string: ")

reversed_string = reverse_string(input_string)

print("Reversed string:", reversed_string)

#source code --> clcoding.com 

Code Explanation:

def reverse_string(s):

def reverse_string(s)::

This line defines a function named reverse_string.

The function takes a single parameter s, which represents the string to be reversed.

if len(s) <= 1:

        return s

if len(s) <= 1::

This is the base case for the recursion. It checks if the length of the string s is less than or equal to 1.

A string of length 0 (empty string) or 1 is its own reverse, so the function directly returns the string as is.

This condition prevents further recursive calls and ensures the recursion stops.

return s:

If the condition len(s) <= 1 is true, the string s is returned without any further processing.

    return reverse_string(s[1:]) + s[0]

reverse_string(s[1:]):

This is the recursive case.

The function calls itself with a smaller substring of s, obtained by slicing the string from the second character onward (s[1:]).

This effectively removes the first character of the string for the current recursive call.

+ s[0]:

The first character of the string (s[0]) is added to the end of the reversed substring returned by the recursive call.

This builds the reversed string step by step.

Recursive Process:

Each recursive call processes a smaller part of the string until the base case is reached, where the string has length 1 or 0.

The reversed parts are then combined as the recursion "unwinds."

input_string = input("Enter a string: ")

input():

This function prompts the user to enter a string. The prompt text "Enter a string: " is displayed.

The user’s input is stored in the variable input_string.

reversed_string = reverse_string(input_string)

The reverse_string function is called with input_string as the argument.

The function returns the reversed version of the input string, which is stored in the variable reversed_string.

print("Reversed string:", reversed_string)

print():

Outputs the reversed string to the console.

The string "Reversed string:" acts as a label, and the value of reversed_string is printed after it.