mapもどき

STLのmapのようなもの

STLのmapのようにキーとデータのペアを格納する簡単な低機能コンテナをvectorを使って作ってみた実験。iteratorとかはありません。

#include <iostream>
#include <vector>
#include <string>

using namespace std;

template<class _Tkey,class _Tdata>
class mymap
{
public:
    _Tdata& operator[](const _Tkey& key);
    void add(const _Tkey& key,const _Tdata& data);
private:
    struct pair
    {
        _Tkey key;
        _Tdata data;
    };
    vector<pair> t;
};

template<class _Tkey,class _Tdata>
_Tdata& mymap<_Tkey,_Tdata>::operator[](const _Tkey& key)
{
    pair tmp;
    
    vector<pair>::iterator i = t.begin();
    for(;i != t.end();i++){
        if(i->key == key)
            return i->data;
    }

//not found
    tmp.key = key;

t.push_back(tmp);
    return (t.back()).data;
}

template<class _Tkey,class _Tdata>
void mymap<_Tkey,_Tdata>::add(const _Tkey& key,const _Tdata& data)
{
    pair tmp;
    tmp.key = key;
    tmp.data = data;

t.push_back(tmp);
}

int main()
{
    mymap<char,int> pu;
    mymap<int,string> pi;
    mymap<string,string> pe;
        
    pu.add('a',1);
    pu.add('z',26);

pi.add(1,string("Hello!"));
    pi.add(2,string("Bye!"));

pe.add(string("I am a "),string("student."));
    pe.add(string("My name is "),string("Bush."));

cout << "-- use pu --" << endl;
    cout << pu['a'] << endl;
    cout << pu['z'] << endl;

pu['k'] = 11;
    cout << pu['k'] << endl;

cout << endl << "-- use pi -- " << endl;
    cout << pi[1] << endl;
    cout << pi[2] << endl;
    
    pi[3] = string("Bomber!!");
    cout << pi[3] << endl;

cout << endl << "-- use pe -- " << endl;
    string s1 = "I am a ";
    string s2 = "My name is ";
    
    cout << s1 << pe[s1] << endl;
    cout << s2 << pe[s2] << endl;

string s3 = "I am live in ";

pe[s3] = "Japan.";
    cout << s3 << pe[s3] << endl;

return 0;
}

実行例