Driver Code
int main ( ) { int n = 3 ; cout << n << " rd ▁ Hendecagonal ▁ number : ▁ " ; cout << hendecagonal_num ( n ) ; cout << endl ; n = 10 ; cout << n << " th ▁ Hendecagonal ▁ number : ▁ " ; cout << hendecagonal_num ( n ) ; return 0 ; }