\cleardoublepage

\chapter{Preliminaries}



\ccHtmlNoClassLinks
\begin{ccClassTemplate}{pair<T1, T2>}

\ccSection{Pair}

\ccDefinition

A struct \ccClassName\ is a heterogeneous pair of values. Its data members
are \ccStyle{first} and \ccStyle{second}.

\ccInclude{pair}

\ccCreation
\ccCreationVariable{p}

\ccConstructor{pair(const T1& x, const T2& y);}
             {Introduces a pair.}


\ccOperations

\ccGlobalFunction{template <class T1, class T2> 
	          bool operator==(const pair<T1,T2> &p, const pair<T1,T2> &p1) const;} 
{Test for equality: Two pairs are equal, iff their data members are equal.}


\ccGlobalFunction{template <class T1, class T2>
	          bool operator<(const pair<T1,T2> &p,
	                                  const pair<T1,T2> &p1) const;}
{Lexicographical comparison of two pairs.}


\ccExample

\begin{cprog}
  Employee irene("Irene", "Eneri");
  Employee leo("Leonard", "Eneri");
  typedef int Social_security_number;

  pair<Social_security_number, Employee> p1(7812, irene),  p2(5555, leo);

  assert( p1.first == 7812 );
  assert( p2.second == leo );
  
\end{cprog} 
\end{ccClassTemplate}