C ++ templates notes 5 class templates special

# Include <deque> <br/> # include <string> <br/> # include <stdexcept> <br/> // # include "stack1.hpp" <br/> # include <iostream> <br/> # include <string> <br/> # include <cstdlib> <br/> # include <vector> </P> <p> template <typename t> <br/> class Stack {<br/> PRIVATE: <br/> STD: vector <t> elems; // elements </P> <p> Public: <br/> void push (T const &); // push element <br/> void POP (); // pop element <br/> T top () c Onst; // return top element <br/> bool empty () const {// return whether the stack is empty <br/> return elems. empty (); <br/>}< br/>}; </P> <p> template <typename T> <br/> void stack <t> :: push (T const & ELEM) <br/>{< br/> elems. push_back (ELEM); // append copy of passed ELEM <br/>}</P> <p> template <typename T> <br/> void stack <t> :: pop () <br/>{< br/> If (elems. empty () {<br/> throw STD: out_of_range ("sta CK <>:: POP (): Empty stack "); <br/>}< br/> elems. pop_back (); // remove last element <br/>}</P> <p> template <typename T> <br/> T stack <t >:: top () const <br/> {<br/> If (elems. empty () {<br/> throw STD: out_of_range ("Stack <>:: top (): Empty stack "); <br/>}< br/> return elems. back (); // return copy of last element <br/>}</P> <p> template <> <br/> class Stack <STD :: string >{< br/> PRIVATE: <br/> STD: deque <STD:: String> elems; // elements </P> <p> Public: <br/> void push (STD: String const &); // push element <br/> void POP (); // pop element <br/> STD: String top () const; // return top element <br/> bool empty () const {// return whether the stack is empty <br/> return elems. empty (); <br/>}< br/>}; </P> <p> void stack <STD: String >:: push (STD :: string const & ELEM) <br/>{< br/> elems. push_back (ELEM); // append copy of PA Ssed ELEM <br/>}</P> <p> void stack <STD: String >:: POP () <br/>{< br/> If (elems. empty () {<br/> throw STD: out_of_range <br/> ("Stack <STD: String >:pop (): Empty stack "); <br/>}< br/> elems. pop_back (); // remove last element <br/>}</P> <p> STD: String Stack <STD: String >:: top () const <br/> {<br/> If (elems. empty () {<br/> throw STD: out_of_range <br/> ("Stack <STD: String >:: top (): Empty stack "); <br/>}< br/> Return elems. back (); // return copy of last element <br/>}</P> <p> int main () <br/>{< br/> try {<br/> stack <int> intstack; // stack of ints <br/> stack <STD: String> stringstack; // stack of strings </P> <p> // manipulate int stack <br/> intstack. push (7); <br/> STD: cout <intstack. top () <STD: Endl; <br/> intstack. pop (); </P> <p> // manipulate String Stack <br/> stringstack. push ("hello"); <br/> STD :: Cout <stringstack. top () <STD: Endl; <br/> stringstack. pop (); <br/> stringstack. pop (); <br/>}< br/> catch (STD: exception const & Ex) {<br/> STD: cerr <"exception: "<ex. what () <STD: Endl; <br/> return exit_failure; // exit program with error status <br/>}</P> <p>/* <br/> the class template is special, you can optimize the implementation of a specific type, or overcome the limitations of a specific type in the instantiation class template <br/>. If you want to create a class template, all member functions of the class template must be customized. <Br/> 7 <br/> Hello <br/> exception: Stack <STD: String >:: POP (): empty stack <br/> the execution result of the code above shows that it calls and executes the special function template <br/> */