[C + +] STL Extraction Learning

STL Extraction Learning

First, the Extraction template class implementation

Iterator class: A collection of common properties for templates, and other classes only need to integrate that class. This example includes only the Value_type attribute for learning.

Iterator_traits Class: Attribute extraction class.

/*********************************** author:szyu** date:2017.3.1***************************************/#ifndef _ _szyu_iterator__#define __szyu_iterator__template <typename t>class iterator_traits{public:typedef TypeName T: : Value_type Value_type;}; Template <typename t>class iterator{public:typedef T value_type;}; #endif

/******************************                                                              ** author : szyu** date :  2017.3.1*************************************/#ifndef  __szyu_head__#define __szyu_head__# include  "Iterator.h" Template <typename t>class test : public iterator <t>{};template <typename t>typename iterator_traits<t>::value_typefunction (  int num1, int num2 ) {    std::cout <<  "Traits  function int. "  << std::endl;    return num1 + num2;} Template <typEname t>typename iterator_traits<t>::value_typefunction ( double num1, double  num2 ) {    std::cout <<  "traits function double."  << std::endl;    return num1 + num2;} #endif

two, test case

/*************************                                                                   ** author :  szyu** date : 2017.3.1***********************************/#include  <iostream># include  "Head.h" Voidtest1 () {    int v1 = function<test<int>  > (1, 2);     std::cout <<  "v1 = "  < < v1 << std::endl;    double v2 = function<test <double> > ( 1.1, 2.2 );    std::cout <<  "v2  =  "&NBSP;&LT;&LT; v2 << std::endl;} Intmain ( int argc, char *argv[] ) {    test1 ();     return 0;}

Third, test results

Traits function int.v1 = 3Traits function Double.v2 = 3.3

[C + +] STL Extraction Learning