Program 21ST VERSION 1 in C++

PROBLEM STATEMENT :

Find the longest palindrome in a given string

SOLUTION :

//solves in o(n^3)

#include <cstdio>

#include <iostream.h>

#include <string.h>

using namespace std;

string strrev(string s)

{

int n=s.length()/2;

char temp;

for(int i=0; i<n; i++)

{

temp = s[i];

s[i]=s[s.length()-i-1];

s[s.length()-i-1]=temp;

}

cout<<" "<<s;

return s;

}

string longpalin(string s1)

{

int pos=0;

int len=0;

if(s1.length() == 0)

{

return "";

}

for( int i=0; i<s1.length(); i++)

{

for( int j=i+1; j<=s1.length()-i ;j++)

{

cout<<"\n\nstring : "<<s1.substr(i,j);

if(s1.substr(i,j) == (strrev(s1.substr(i,j))) && j>len)

{

pos=i;

len=j;

}

}

}

return s1.substr(pos,len);

}

int main()

{

string s;

cout<<"\n\nEnter a string : ";

getline(cin,s,'\n');

cout<<"\n\nLongest Palindrome is : "<<longpalin(s);

}