Python Program:

Example:

s1=input("Enter your string : ")
reverse = ""
l=len(s1)-1
while l!=-1 :
  reverse+=s1[l]
  l-=1
print("Your reversed string : ",reverse)

Output:

  Enter Your string : fun with code
  Your reversed string : edoc htiw nuf

Main Logic :

# varibale 'l' holds length of string - 1 (since index starts from 0)
while l!=-1 :
  reverse+=s1[l]
  l-=1