(Palindromes) Write a function template palindrome that takes a vector parameter and re- turns true or false according to whether the vector does or does not read the same forward as back- ward (e.g., a vector containing 1, 2, 3, 2, 1 is a palindrome, but a vector containing 1, 2, 3, 4 is not).

Question

What will be an ideal response?

Answer 1

```
#include
#include // vector class-template definition
using namespace std;

// function template palindrome definition
template < typename X >
bool palindrome( const vector< X > &vec )
{
typename vector< X >::const_reverse_iterator r = vec.rbegin();
typename vector< X >::const_iterator i = vec.begin();

while ( r != vec.rend() && i != vec.end() )
{
if ( *r != *i ) // values are not equal
return false;

++r;
++i;
} // end while

return true; // the vector is a palindrome
} // end function palindrome

// function template printVector definition
template < typename Y >
void printVector( const vector< Y > &vec )
{
typename vector< Y >::const_iterator i;

for ( i = vec.begin(); i != vec.end(); ++i )
cout << *i << ' ';
} // end function palindrome

int main()
{
vector< int > iv;
vector< char > ic;
int x = 0;

for ( int i = 75; i >= 65; i-- )
{
iv.push_back( i );
ic.push_back( static_cast< char > ( i + x ) );

if ( i <= 70 )
x += 2;
} // end for

printVector( iv );
cout << ( palindrome( iv ) ? " is " : " is not " ) << "a palindrome\n";

printVector( ic );
cout << ( palindrome( ic ) ? " is " : " is not " ) << "a palindrome\n";
} // end main
```
75 74 73 72 71 70 69 68 67 66 65 is not a palindrome
K J I H G F G H I J K is a palindrome