Vector的实现

本文模仿STL中的vector，自己实现其基本功能，主要包括：

• 初始化列表形式的初始化 eg. vector<int> v{1,2,3,4,5};
• 构造函数与析构函数，包括赋值构造、移动构造
• 拷贝函数，包括赋值拷贝、移动拷贝
• 基础API函数：
• • resize( ), reserve( ), size( ), empty( )
• • push_back( ), pop_back( ), begin( ), end( )
• • operator 等等

  注意，模板类不建议使用分离编译，感觉C++的模板就是个坑。
  下面直接贴代码：

#ifndef VECTOR_H#define VECTOR_H#include <algorithm>#include <initializer_list>template <typename Object>class Vector{public:    Vector( std::initializer_list <Object> l) : theSize(l.size())           //初始化列表    {        objects = new Object[l.size()+SPARE_CAPACITY];        auto it = l.begin(); int k=0;        for( ; it!=l.end(); ++it,++k)           objects[k] = *it;    }    explicit Vector( int initSize = 0 ): theSize(initSize),             //禁止自动转换        theCapacity{initSize+SPARE_CAPACITY}    {    objects = new Object[theCapacity];    }    Vector(const Vector& rhs): theSize(rhs.theSize),        theCapacity(rhs.theCapacity), objects(nullptr){        objects = new Object[theCapacity];        for(int k=0; k<theSize; ++k)           objects[k] = rhs.objects[k];    }    Vector& operator = (const Vector & rhs)    {        Vector copy = rhs;        std::swap(*this, copy);        return *this;    }    Vector(Vector && rhs) : theSize(rhs.theSize),        theCapacity(rhs.theCapacity), objects(rhs.objects)    {        rhs.objects = nullptr;        rhs.theSize = 0;        rhs.theCapacity = 0;    }    Vector & operator = (Vector &&rhs)    {        std::swap(theSize, rhs.theSize);        std::swap(theCapacity, rhs.theCapacity);        std::swap(objects, rhs.objects);        return *this;    }    ~Vector()    {        delete []objects;    }    void resize( int newSize)    {        if(newSize > theCapacity)            reserve( newSize*2 );        theSize = newSize;    }    void reserve( int newCapacity)    {        if( newCapacity < theSize)            return;        Object *newArray = new Object[newCapacity];        for(int k=0; k<theSize; ++k)            newArray[k] = std::move(objects[k]);        theCapacity = newCapacity;        std::swap(objects, newArray);        delete []newArray;    }    Object & operator [] (int index)    {        return objects[index];    }    const Object& operator [](int index) const    {        return objects[index];    }    bool empty() const    {        return size()==0;    }    int size() const    {        return theSize;    }    int capacity() const    {        return theCapacity;    }    void push_back(const Object & x)    {        if(theSize == theCapacity)            reserve(2*theCapacity+1);        objects[theSize++] = x;    }    void push_back(Object && x)    {        if(theSize == theCapacity)            reserve(2*theCapacity+1);        objects[theSize++] = std::move(x);    }    void pop_back()    {        --theSize;    }    const Object & back() const    {        return objects[theSize-1];    }    typedef Object * iterator;    typedef const Object * const_iterator;    iterator begin()    {        return &objects[0];    }    const_iterator begin() const    {        return &objects[0];    }    iterator end()    {        return &objects[size()];    }    const_iterator end() const    {        return &objects[size()];    }    static const int SPARE_CAPACITY = 16;private:    int theSize;    int theCapacity;    Object * objects;};#endif // VECTOR_H

main.cpp:

#include <iostream># include "vector.h"using namespace std;int main(int argc, char *argv[]){    Vector<int> v{1,2,3};  //for(int i=0;i<5;++i) v.push_back(i);    for(auto i:v)        cout<<i<<" ";    //cout << "Hello World!" << endl;    return 0;}