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Palindrome thru recursion

 
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Palindrome thru recursion
naash
post 5 Sep, 2007 - 07:00 AM
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1. Write a recursive for that determines if a string is palindrome. If it is, print the string le one line followed by “is a particular “or “is not a palindrome” as the case may be. Ignore spaces and case.


I have done this by iteration....here's my logic

CODE

char s[10];
int flag=1;
for(i=0;i<l;i++)
  if(s[i]!=s[l-i-1])
     {
        flag=0;
        break;
     }
if(flag==0)
   cout<<"Not a palindrome";
if(flag!=0)
  cout<<"Palindrome";


But recursion puzzles me. Now recursion requires a testing cond^n and stopping cond^n.

Can anybody tell me what these 2 conditions should be so that I can start off with programming using recursion ?

This post has been edited by naash: 5 Sep, 2007 - 07:02 AM
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Martyr2
post 5 Sep, 2007 - 08:24 AM
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Your test condition will be something along the lines of...

CODE

if (str[0] == str[length-1]) {                        
      return isPalindrome (str+1, length-2);
}
else {
      return 0; // not a palidrome
}


And your stop condition will be along the lines of if (length<1) return 1; if it is a palidrome otherwise your else in the if condition above will return 0 if it is not a palidrome.

Hope this gives you the push you needed. smile.gif
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naash
post 5 Sep, 2007 - 05:33 PM
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Joined: 25 Aug, 2007
Posts: 77


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QUOTE(Martyr2 @ 5 Sep, 2007 - 09:24 AM) *

Your test condition will be something along the lines of...

CODE

if (str[0] == str[length-1]) {                        
      return isPalindrome (str+1, length-2);
}
else {
      return 0; // not a palidrome
}


And your stop condition will be along the lines of if (length<1) return 1; if it is a palidrome otherwise your else in the if condition above will return 0 if it is not a palidrome.

Hope this gives you the push you needed. smile.gif



Thank you so much it worked !!! smile.gif
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