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 = 0; 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 + 1 << ") " << row[d] << endl;
            
        }
        else
        {
            cout << "This word can not be found in this passage! Please input a word again: " << endl;    
        }
    in.close();

    return 0;
}