C++Primer笔记——文本查询程序（原创，未使用类）

 #include <iostream>
 #include <vector>
 #include <set>
 #include <map>
 #include <fstream>
 #include <sstream>
 #include <string>

 using namespace std;

 int main()
 {
     ifstream in;
     in.open("C:\\Users\\HP\\Desktop\\passage.txt");
     vector<string>row;                   //使用vector<string>来保存整个输入文件的一份拷贝，输入文件的每行保存为其中的每一个元素
     map<string, set<int>>word_and_row;   //使用map将每个单词与它出现的行号set关联起来，使用set可以保证行号不会重复且升序保存
     string s;
     while (getline(in, s))
     {
         row.push_back(s);
     }
     for (size_t i = ; i < row.size(); ++i)
     {
         string word;
         istringstream read(row[i]);     //使用istringstream来将每行分解为单词
         while (read >> word)
             word_and_row[word].insert(i);
     }

     string s1;                          //s1为待查找的单词。注意：待查找的单词不能与句号或逗号连在一起！
     while (cin >> s1 && s1 != "q" )     //输入q时终止输入
         if (word_and_row.find(s1) != word_and_row.end())
         {
             int i = word_and_row[s1].size();
             cout << s1 << " occurs " << i << " times" << endl;
             for (auto d : word_and_row[s1])
                 cout << "(line " << d +  << ") " << row[d] << endl;

         }
         else
         {
             cout << "This word can not be found in this passage! Please input a word again: " << endl;
         }
     in.close();

     return ;
 }