C++文本查询程序 定义类管理数据 用智能指针 用StrBlob代替vector<string> C++Primer 练习12.32

// StrBlob类的定义.h文件#ifndef STRBLOB_H#define STRBLOB_H#include<vector>#include<string>#include<initializer_list>#include<memory>using namespace::std;class StrBlob{friend class QueryResultStrBlob;public:typedef vector<string>::size_type size_type;StrBlob();StrBlob(initializer_list<string>il);StrBlob(const StrBlob&); //拷贝构造size_type size() const { return data->size(); }bool empty() const { return data->empty(); }//添加和删除元素void push_back(const string& t) { data->push_back(t); }void pop_back();//元素访问string& front();string& back();const string& front() const;const string& back() const;const string& backi(size_type i) const;private:shared_ptr<vector<string>>data;void check(size_type i, const string& msg) const;};

//StrBlob类的实现.cpp文件
#include "StrBlob.h"
StrBlob::StrBlob():data(make_shared<vector<string>>()) { }
StrBlob::StrBlob(initializer_list<string>il) : data(make_shared<vector<string>>(il)) { }
StrBlob::StrBlob(const StrBlob& strb)    //拷贝构造,输入一定是常量类的引用
{
data = strb.data;
}
void StrBlob::check(size_type i, const string& msg) const
{
if (i >= msg.size())
throw out_of_range(msg);
}
void StrBlob::pop_back()
{
check(0, "pop_back on empty StrBlob");
data->pop_back();
}
string& StrBlob::front()
{
check(0,"front on empty StrBlob");
return data->front();
}
string& StrBlob::back()
{
check(0,"back on empty StrBlob");
return data->back();
}
const string& StrBlob::front()  const
{
check(0, "front on empty StrBlob");
return data->front();
}
const string& StrBlob::back()  const //后面的const表示不能修改this指针，前面的const表示返回类型是const
{
check(0, "back on empty StrBlob");
return data->back();
}

const string& StrBlob::backi(size_type i) const
{
check(0, "return element on empty StrBlob");
return *(data->begin() + i);
}

// TextQueryStrBlob，QueryResultStrBlob类的定义.h文件
#ifndef	TEXTQUERYSTRBLOB_H
#define TEXTQUERYSTRBLOB_H
#include<memory>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<fstream>
#include<sstream>
#include "StrBlob.h"
class QueryResultStrBlob;
class TextQueryStrBlob
{
public:
using line_no = std::vector<std::string>::size_type;
TextQueryStrBlob(std::ifstream&);
QueryResultStrBlob query(const std::string&) const;
private:
StrBlob file; //输入文件,里面的智能指针指向一个空的vector<string>
std::map<std::string, std::shared_ptr<std::set<line_no>>> wm;//每个单词到到它所在行号的集合的映射
};

class QueryResultStrBlob
{
friend std::ostream& print(std::ostream&, const QueryResultStrBlob&);
public:
using line_no = std::vector<std::string>::size_type;
QueryResultStrBlob(std::string s,
std::shared_ptr<std::set<line_no>> p,const StrBlob& f) :
sought(s),lines(p),file(f) { }
private:
std::string sought;  //查询单词
std::shared_ptr<std::set<line_no>> lines; //出现的行号
StrBlob file; //输入的文件
};
#endif;

// TextQueryStrBlob，QueryResultStrBlob类的实现.cpp文件#include "TextQueryStrBlob.h"using namespace::std;TextQueryStrBlob::TextQueryStrBlob(ifstream& infile){	string str;while (getline(infile, str)){file.push_back(str);int num = file.size() - 1;  //当前行号istringstream istr(str);string word;while (istr >> word){auto &line = wm[word];  //line为行号的set的指针，如果word是第一次出现，则先添加word后绑定，否则直接line和指针绑定if (!line) //如果指向的是空对象，说明此word还没有创建新的set，要创建新的set，为后续插入行号做准备line.reset(new set<line_no>);//重新分配对象给lineline->insert(num);              //如果一个单词在一行中出现多次，则只记录一次}}}QueryResultStrBlob TextQueryStrBlob::query(const string& word) const{//查询单词，把结果传给QueryResultauto ret = wm.find(word);if (ret != wm.end())return QueryResultStrBlob(word, ret->second,file);else{static shared_ptr<set<line_no>> p(new set<line_no>);return QueryResultStrBlob(word, p,file);}}string make_plural(size_t ctr, const string &word, const string &ending){return(ctr > 1) ? word + ending : word;}ostream  &print(ostream& out, const QueryResultStrBlob& qr){out << qr.sought << " occurs " << qr.lines->size() << make_plural(qr.lines->size(), "times", "s") << endl;for (auto wq = qr.lines->begin(); wq != qr.lines->end(); ++wq){out << "(line " << *wq + 1 << ")" << qr.file.backi(*wq)<< endl;}return out;}

//测试文件.cpp#include<iostream>#include "TextQueryStrBlob.h"using namespace std;void RunQueriesStrBlob(ifstream &infile){TextQueryStrBlob tq(infile);while (true){cout << "enter word to look for,or q to quit: ";string s;if (!(cin >> s) || s == "q") break;print(cout, tq.query(s)) << endl;}}int main(){ifstream infile("wordtext.txt");RunQueriesStrBlob(infile);return 0;}

输入文件：输出结果：