读书笔记（C++）——【关联容器】

#include<iostream>
#include<fstream>
#include<sstream>
#include<string>
#include<cctype>
#include<vector>
#include<map>
#include<set>
#include <stdexcept>
#include<stdlib.h>
using namespace std;

//map
//表10 - 5 insert
1,m.insert(e);
2,m.insert(beg,end);
3,m.insert(iter,e)
//10.3.4//使用下标访问
    map<string,int> word_count;
    string word;
    while(cin>>word)
        ++word_count[word];

    word_count.insert(make_pair("Anna",1));
or  typedef map<string,int>::value_type calType;
    word_count(valuType("Anna",1));
//10.3.5 map insert使用
    map<string,int> word_count;
    while(cin>>word)
    {
        pair<map<string,int>::iterator,bool> ret =
                        word_count.insert(make_pair(word,1));
        if(!ret.second)
            ++ret.first->second;
/    }
//表10 — 6 不修改map对象的查询操作
m.count(k);
m.find(k);
    int occurs = 0;
    map<string,int>::iterator it = word_count.find("foobar");
    if(it != word_count.end())
        occurs = it->second;
//10.3.7 map中删除对象
//表10 - 7
m.erase(k);//返回1 or 0
m.erase(p);//p为迭代器；
m.erase(b,e);
//10.3.8 遍历
    map<string,int>::iterator map_it = word_count.begin();
    while(map_it != word_count.end())
        {
        cout<<map_it->first<<":"<<map_it->second<<endl;
        ++map_it;
        }
//10.3.9 单词转换
int main(int argc,char **argv)
{
    map<string,int> trans_map;
    string key,value;
    if(argc != 3)
        throw runtime_error("wrong number of arguments");
    ifstream map_file;
    if(!open_file(map_file,atgv[1]))
        throw runtime_error("no transformation file");
    while(map_file>>key>>value)
        trans_map.insert(make_pair(key,value));
    ifstream input;
    if(!open_file(input,argv[2]))
        throw runtime_error("no input file");
    while(getline(input,line))
    {
        istringstream stream(line);
        string word;
        bool firstword = true;
        while(stream>>word)
        {
            map<string,string>::const_iterator map_it =
                                trans_map.find(word);
            if(map_it != trans_map.end())
                word = map_it->second;
            if(firstword)
                firstword = false;
            else
                cout<<" ";
            cout<<word;
        }
        cout<<endl;
    }
}
//10.4.1 set定义和使用
    vector<int> ivec;
    for(int i = 0;i != 10;i++)
    {
        ivec.push_back(i);
        ivec.push_back(i);
    }
    set<int> iset(ivec.begin(),ivec.end())
    cout<<ivec.size()<<endl;//prints 20;
    cout<<iset.size()<<endl;//prints 10;
//在set中添加元素
    set<string> set1;
    set1.insert("the");
    set1.insert("and");
or
    set<int> set2;
    set2.insert(ivec.begin(),ivec.end());
//获取元素
    iset.find(1)//returns iterator that refers to the element with the key == 1
    iset.find(11)//returns iterator == iset.end();
    iset.count(1)//returns 1;
    iset.count(11)//returns 0;

    set<int>::iterator set_it; = iset.find(1);
    *set_it = 11;//error:keys in a set are read_only;
    cout<<*set_it<<endl;
//10.4.2 单词排除集
void restricted_wc(ifstream &remove_file,
                   map<string,int> &cord_count)
{
    set<string> excluded;
    string remove_word;
    while(remove_file>>remove_word)
        excluded.insert(remove_word);
    string word;
    while(cin>>word)
        if(!excluded.count(word))
        ++word_count[word];
}
//10.5 multimap 和 multiset
//10.5.1 元素添加和删除
    authors.insert(make_pair(
        string("Barth,John")
        string("Sot-Weed Factor")));
    authors.insert(make_pair(
        string("Barth,John")
        string("Lost in the Funhouse")));

    multimap<string,string> authors;
    string search_item("Kazuo Ishiguro");
    multimap<string,string>::size_type cnt =
                    authors.erase(search_item);
//在multimap和multiset中查找元素
//1.使用find和count操作
    string search_item("WG");
    typedef multimap<string,string>::size_type sz_type;
    sz_type entrise = authors.count(search_item);
    multimap<string,string>::iterator iter =
                        authors.find(search_item);

    for(sz_type cnt = 0;cnt != entrise;++cnt,++iter)
        cout<<iter->second<<endl;
//2.面向迭代器解决
//表10 - 8 返回迭代器的关联容器操作
m.lower_bound(K)    //返回一个迭代器，指向键不小于K的第一个元素
m.upper_bound(K)    //返回一个迭代器，指向键大于k的第一个元素
m.equal_range(k)    //返回一个迭代器的pair对象
                    //它的first成员等价于m.lower_bound(k),second成员等价于m.upper_bound(k)

//
    typedef multimap<string,string>::iterator authors_iter;
    authors_iter beg = authors.lower_bound(search_item);
                _end = authors.upper_bound(search_item);

    while(beg != _end)
    {
        cout<<beg->second<<endl;
        ++beg;
    }
//直接调用equal_range解决
    pair<authors_iter,authors_iter>
            pos = authors.equal_range(search_item);

    while(pos.first != pos.second)
    {
        cout<<pos.first->second<<endl;
        ++pos.first;
    }
//容器综合应用：文本查询程序
#include<iostream>
#include<fstream>
#include<sstream>
#include<string>
#include<cctype>
#include<vector>
#include<map>
#include<set>
#include <stdexcept>
#include<stdlib.h>
class TextQuery
{
public:
    typedef std::vector<std::string>::size_type line_no;
    void read_file(std::ifstream &is)
    {
        store_file(is);build_map();
    }
    std::set<line_no> run_query(const std::string&) const;
    std::string text_line(line_no) const;
private:
    void store_file(std::ifstream&);
    void build_map();
    std::vector<std::string> lines_of_text;
    std::map<std::string,std::set<line_no> > word_map;
};
void TextQuery::store_file(std::ifstream &is)
{
    std::string textline;
    while(getline(is,textline))
        lines_of_text.push_back(textline);
}
void TextQuery::build_map()
{
    for(line_no line_num = 0;
        line_num != lines_of_text.size();
                                ++line_num)
    {
        std::istringstream line(lines_of_text[line_num]);
        std::string word;
        while(line>>word)
            word_map[word].insert(line_num);
    }
}
std::set<TextQuery::line_no>
TextQuery::run_query(const std::string &query_word) const
{
    std::map<std::string,std::set<line_no> >::const_iterator
                                loc = word_map.begin();
    if(loc == word_map.end())
        return std::set<line_no>();
    else
        return loc->second;
}
std::string TextQuery::text_line(line_no line)const
{
    if(line<lines_of_text.size())
        return lines_of_text[line];
    throw std::out_of_range("line number out of range");
}
void print_results(const std::set<TextQuery::line_no>& locs,
                  const std::string& sought,const TextQuery &file);
                  std::ifstream& open_file(std::ifstream &in,const std::string &file)
{
    in.close();
    in.clear();
    in.open(file.c_str());
    return in;
}
std::string make_plural(size_t ctr,const std::string &word,const std::string &ending)
{
    return (ctr==1)?word:word + ending;
}
int main(int argc,char **argv)
{
    std::ifstream infile;
    if(argc < 2 || !open_file(infile,argv[1]))
    {
        std::cerr<<"No input file!"<<std::endl;
        return EXIT_FAILURE;
    }
    TextQuery tq;
    tq.read_file(infile);

    while(true)
    {
        std::cout<<"enter word to look for,or q to quit: ";
        std::string s;
        std::cin>>s;

        if(!std::cin || s == "q")
        break;
        std::set<TextQuery::line_no> locs = tq.run_query(s);
        print_results(locs,s,tq);
    }
    return 0;
}
void print_result(const std::set<TextQuery::line_no>& locs,
                  const std::string& sought,const TextQuery &file)
{
    typedef std::set<TextQuery::line_no> line_nums;
    line_nums::size_type sz = locs.size();
    std::cout<<"\n"<<std::cout<<sought<<" occurs"<<sz<<" "
                    <<make_plural(sz,"time","s")<<std::endl;

    line_nums::const_iterator it = locs.begin();

    for(;it != locs.end();++it)
    {
        std::cout<<"\t(line "
            <<(*it) + 1<<") "
            <<file.text_line(*it)<<std::endl;
    }
}