??????Vector?????

???????????? ???????[ 2013/6/7 9:57:43 ] ????????

??????????????? ????????????????Vector???й???????? Link????

???????????? Vector?洢?Щ????????????????? clear() ?????沢??????????????????????й??????????????

????“vector ?? clear ????? capacity ?? ????? swap ?????? vector??”

???????????????????????????????????????? vector swap clear ??????????????????????????????????Щ?????????

??????????????????? ??Effective STL???е?“????17”????????

??????vector??string?????????????????????????????????????????????clear?? ????и??????????????capacity????????????????????檔 ??????????????????????????????????????????????С??????? ???????裨shrink to fit??

??????Effective STL?????????????????

    vector<type> v;
    //.... ??????????????v
    //.... ???????v?е???????
    vector<type>(v).swap(v);
    //???v???????????????????????????????????
    //????string???????????????
    string(s).swap(s);

???????????????????????????vector??￡??????????????????? ?????????????С????????????????????????????????vector v???? ????????????????н?????????????????????????????????v?????? ????????????????????????????????????????vector????????????????

?????????????????д????????????￡?

    #include <iostream>
    #include <vector>

    using namespace std;

    vector <string> v;
    char ch;

    int main ()
    {

        for(int i=0; i<1000000; i++)
            v.push_back("abcdefghijklmn");
        cin >> ch;
        // ???????????? ???54M

        v.clear();
        cin >> ch;
        // ?????μ?飬 ??????54M

        cout << "Vector ?? ?????" << v.capacity() << endl;
        // ???????? 1048576

        vector<string>(v).swap(v);

        cout << "Vector ?? ?????" << v.capacity() << endl;
        // ????????0
        cin >> ch;
        // ?????棬????? 10M+ ??????????
        return 0;
    }