C++ Primer : 第十二章 : 动态内存之shared_ptr类实例：StrBlob类

来源：互联网发布：歌华有线网络编辑：程序博客网时间：2024/06/04 00:20

StrBlob是一个管理string的类，借助标准库容器vector，以及动态内存管理类shared_ptr，我们将vector保存在动态内存里，这样就能在多个对象之间共享内存。

定义StrBlob类：

#include <iostream>#include <stdexcept>#include <memory>#include <vector>#include <string>#include <initializer_list>#include <utility>#include <stdexcept> // for out_of_rangeclass StrBlob{public:typedef std::vector<std::string>::size_type size_type;typedef std::shared_ptr<std::vector<std::string>> shdptrStrVec;StrBlob();StrBlob(std::initializer_list<std::string> il);StrBlob(std::vector<std::string>::iterator& left, std::vector<std::string>::iterator& right);StrBlob(std::vector<std::string>& vec);size_type size() const { return data->size(); }bool empty() const { return data->empty();}void push_back(const std::string& str ){ data->push_back(str);}void pop_back();// 访问元素std::string& front();std::string& back();// const 版本const std::string& front() const;const std::string& back() const;std::string& at(size_type i){ return data->at(i); }StrBlob& operator = (StrBlob& blob);private:std::shared_ptr<std::vector<std::string>> data;void check(size_type i, const std::string& msg) const;};

StrBlob的实现：

StrBlob::StrBlob() : data(std::make_shared<std::vector<std::string>>()){}StrBlob::StrBlob(std::initializer_list<std::string> il) : data(std::make_shared<std::vector<std::string>> (il)){}StrBlob::StrBlob(std::vector<std::string>::iterator& left, std::vector<std::string>::iterator& right) : data(std::make_shared<std::vector<std::string>>(left, right)){}StrBlob::StrBlob(std::vector<std::string>& vec) : data(std::make_shared<std::vector<std::string>>(vec)) {}void StrBlob::check(size_type i, const std::string& msg) const{if (i >= data->size())throw std::out_of_range(msg);}std::string& StrBlob::front(){check(0, "");return data->front();}std::string& StrBlob::back(){check(0, "");return data->back();}const std::string& StrBlob::front() const{check(0, "");return data->front();}const std::string& StrBlob::back() const{check(0, "");return data->back();}void StrBlob::pop_back(){check(0, "");data->pop_back();}StrBlob& StrBlob::operator =(StrBlob& blob) {this->data = blob.data;return *this;}

0 0