c++八股文stl模板库01-20第11条：vector如何释放内存

[SIIYIIX]

下边代码第一行swap的作用应该是把Vec中多余的空间清除掉，相当于shrink_to_fit

#include <iostream>
#include <vector>
using namespace std;

int main ()
{
    vector<int> vec (100,100);   // three ints with a value of 100
    vec.push_back(1);
    vec.push_back(2);
    cout <<"vec.size(): " << vec.size() << endl;
    cout <<"vec.capasity(): " << vec.capacity() << endl;

    vector<int>(vec).swap(vec); //清空vec中多余的空间，相当于vec.shrink_to_fit();

    cout <<"vec.size(): " << vec.size() << endl;
    cout <<"vec.capasity(): " << vec.capacity() << endl;

    vector<int>().swap(vec); //清空vec的全部空间

    cout <<"vec.size(): " << vec.size() << endl;
    cout <<"vec.capasity(): " << vec.capacity() << endl;

    return 0;
}
/*
    运行结果：
    vec.size(): 102
    vec.capasity(): 200
    vec.size(): 102
    vec.capasity(): 102
    vec.size(): 0
    vec.capasity(): 0
 */

[forthespada]

thanks，已做补充！