#include <iostream>
#include <string>
#include <cctype>
using namespace std;

bool is_palindrome( const string& line );

int main()
{
  cout << "Type in a sentence and I will determine\n"
       << "whether it's a palindrome or not.\n";
  // e.g. "Madam, I'm Adam" ==> "madA m'I ,madaM"
  //         ==> "madamimadam"

  // count how many sentences are palindromes
  unsigned int count = 0;

  string line;
  while ( getline( cin, line ) )   // CTRL-D or CTRL-Z to exit
  {
    if ( is_palindrome( line ) )
    {
      count++;
      cout << "PALINDROME: " << line << endl;
    }
  }

  cout << "Found " << count << " lines containing palindromes.\n";
  return 0;
}

bool is_palindrome( const string& line )
{
  // HINT: use a local string variable
  //       to hold a copy of line without spaces, punctuation, etc.
  //       (also converted entirely to lowercase)
  string temp;
  string::const_iterator i;

  for ( i = line.begin() ; i != line.end() ; i++ )
  {
    if ( isalpha( *i ) )   // only copy over alpha characters
    {
      temp.push_back( tolower( *i ) );   // convert to lowercase
    }
  }

  // HINT: use two iterators to compare the first letter
  //       with the last letter, then the second letter
  //       with the second-to-last letter, etc.
  //       (returning false if a mismatch occurs)
  string::const_iterator j;

  // e.g.  "madamimadam"
  //        ^         ^
  //        i         j
  i = temp.begin();
  j = temp.end();    // or tack on  - 1;
  j--; // now we're pointing to the last element

  // while ( i != j )  <== only works if size is odd
  while ( i < j )
  {
    // compare characters:
    if ( *i != *j ) {
      return false;
    }

    i++;  j--;
  }

  return true;
}

// another approach:
bool is_palindrome_in_place( const string& line )
{
  // HINT: use two iterators to compare the "normalized"
  //       first letter with the "normalized" last letter,
  //       then the "normalized" second letter to the
  //       "normalized" second-to-last letter, etc.
  //       (returning false if a mismatch occurs)

  return true;
}

// TO DO: find the longest palindrome sentence you can!