C++分析——泛型模板

Bertha 。 2022-05-28 13:47 165阅读 0赞

*  泛型编程的简单示例
 *  模板类：双向循环链表应用
    
     *  定义模板头文件
        
         *  定义双向循环链表节点
         *  定义链表模板迭代器基类
         *  定义链表模板
     *  实现方法

这类是C++的特点，但在实际使用中不经常使用，泛型是指数据类型泛指，特点是面向对象，屏蔽掉参数特征，泛型编程依靠模板实现

# 泛型编程的简单示例 #

template <typename T>
    T func_add(T a,T b)
    {
            return a + b;
    }

实现方法

cout << "test_1 vlaue is " << func_add(3,6) << endl;
        cout << "test_2 vlaue is " << func_add(23.5,45.67) << endl;
        cout << "test_3 vlaue is " << func_add(string("Test 1"),string(" Test 2.")) << endl;
        cout << hex << "test_4 vlaue is " << func_add(0x23,0x78) << endl;

执行结果

test_1 vlaue is 9
    test_2 vlaue is 69.17
    test_3 vlaue is Test 1 Test 2.
    test_4 vlaue is 9b

通过该泛型编程的测试函数，将传入的参数类型直接屏蔽，仅仅服务于符号“+”，对于不同类型的参数或类做不同参数对象的运算符重载处理。

**泛型模板结合类的运输算符重载进行底层操作。**

# 模板类：双向循环链表应用 #

C语言的双向循环链表，用泛型模板编程，忽略变量的定义。

定义模板类仿照C++标准模板使用

## 定义模板头文件 ##

**头文件不带后缀.h**  
**头文件用命名空间名限制内容**  
**namespace CTypeList\{\}**

### 定义双向循环链表节点 ###

template<class T>
     class CNode { public: CNode() :Tdata(0),last(nullptr), next(nullptr) {}; CNode(T tSetdata) :Tdata(tSetdata), last(nullptr), next(nullptr) {} CNode(T tSetdata, CNode<T> *tSetlast) :Tdata(tSetdata), last(tSetlast), next(nullptr) {}; CNode(T tSetdata, CNode<T> *tSetlast, CNode<T> *tSetnext) :Tdata(tSetdata), last(tSetlast), next(tSetnext) {}; public: T Tdata; CNode<T> *last; CNode<T> *next; };

### 定义链表模板迭代器基类 ###

template<class T>
        class iterator //定义迭代器
        {
        public:
            iterator() :_m_pList(nullptr) {}
            iterator(CNode<T> *p_set) :_m_pList(p_set) {}
            ~iterator() {}
    
            T operator*() const {
                return _m_pList->Tdata;
            }
            CNode<T>* operator->() const {
                return _m_pList;
            }
            iterator& operator++() {
                _m_pList = _m_pList->next;
                return *this;
            }
            iterator operator++(int) {
                CNode<T> *tmp = _m_pList;
                _m_pList = _m_pList->next;
                return iterator(tmp);
            }
            bool operator==(const iterator &cmpiter) const {
                return (this->_m_pList == cmpiter._m_pList);
            }
            bool operator!=(const iterator &cmpiter) const {
                return (this->_m_pList != cmpiter._m_pList);
            }
            bool operator<(const iterator &cmpiter) const {
                return (this->_m_pList < cmpiter._m_pList);
            }
            bool operator>(const iterator &cmpiter) const {
                return (this->_m_pList > cmpiter._m_pList);
            }
    
        private:
            CNode<T> *_m_pList;
        };

### 定义链表模板 ###

template<class T>
        class ClistInfo : public iterator<T>
        {
        public:
            ClistInfo():m_siSize(0){
                m_phead = new CNode<T>();
                m_ptail = m_phead;
            }
            ClistInfo(const ClistInfo<T> &x){
                m_phead = new CNode<T>();
                m_ptail = m_phead;
    
                this->m_siSize = x.m_siSize;
                iterator<T> paddlist =  x.begin();
                while ( x.end() != paddlist ){
                        this->push_back(*paddlist);
                        paddlist++;
                }
            }
            virtual ~ClistInfo(){
                this->clear();
                delete m_phead;
                m_phead = nullptr;
            };
    
            inline virtual bool empty() const {
                return !m_siSize;
            }
            inline virtual int size() const {
                return m_siSize;
            }
            virtual void push_back(T addTdata){
                m_ptail->next = new CNode<T>(addTdata,m_ptail,m_phead);
    
                if (nullptr == m_ptail->next){
                    return;
                }
                m_ptail = m_ptail->next;
                m_siSize++;
            }
            virtual void pop_back(){
    
                if (m_phead == m_ptail){
                    return;
                }
    
                m_ptail->last->next = m_ptail->next;
    
                CNode<T> *pdellist = m_ptail;
                m_ptail = m_ptail->last;
    
                delete pdellist;
                pdellist = nullptr;
    
                m_siSize--;
            };
            virtual iterator<T> find(const T findTdata){
    
                    iterator<T> pfindlist = this->begin();
                    while ( this->end() != pfindlist){
                            if(findTdata == pfindlist->Tdata){
                                    return pfindlist;
                            }
                            pfindlist++;
                    }
    
                    return this->end();
            }   
            virtual void clear(){
                while (m_ptail != m_phead){
                    pop_back();
                }
            }
    
            iterator<T> begin() const {
                return iterator<T>(m_phead->next);
            }
    
            iterator<T> end() const {
                return iterator<T>(m_ptail->next);
            }
    
        private:
            CNode<T>        *m_phead;       //表头
            CNode<T>        *m_ptail;       //末端 
            int              m_siSize;
        };

## 实现方法 ##

#include "ClistInfo"
    
    using namespace CTypeList;
    
    void Test(void)
    {
        CTypeList::ClistInfo<int>  CListTest;
        for (int i = 1; i <= 4; ++i)
        {
            CListTest.push_back(i);
        }
    
        CTypeList::ClistInfo<int>::iterator iter = CListTest.begin();
    
        while (CListTest.end() != iter)
        {
            std::cout << "value = " << *iter << std::endl;
            iter++;
        }
    }

Makefile需要引入支持C++11特性，支持nullptr

SRC = $(wildcard ./*.cpp)
    OBJ = $(patsubst %.cpp,%.o,$(SRC))
    VCPP = -std=c++11
    
    CFLAGS = -g -Wall $(INC) $(LIB_INC)
    
    all:$(OBJ)
    
    .cpp.o:
        $(CC) $(CFLAGS) -c $< $(VCPP)
    
    clean:
        rm -rf $(OBJ)

执行结果

$ ./project.o 
    CSystem is called.
    value = 1
    value = 2
    value = 3
    value = 4