#include <iostream>

#include <vector>
using std::vector;

// 随便创建一个结构体
typedef struct Point {
    int x;
    int y;
    int val;

    // 顺带演示统一初始化 (现代C++)
    Point(int x, int y, int value) : x(x), y(y), val(value) {};
};

int main()
{
    // 定义一个 vector
    vector<Point> points;

    // 随便填充一下
    for (size_t i = 0; i < 9000; i++)
    {
        points.push_back(Point(i, i, -99999));
    }

    // clear清理vector
    points.clear();

    // 输出一下 vector 长度和容量
    std::cout << "Vector Size: " << points.size() << std::endl;          // size: 0
    std::cout << "Vector Capacity: " << points.capacity() << std::endl;  // capacity: 12138


    std::cout << "===========================" << std::endl;

    // 从这里将 vector 的容量强制置空
    vector<Point>().swap(points);

    // 再次输出一下
    std::cout << "Vector Size: " << points.size() << std::endl;         // siez: 0
    std::cout << "Vector Capacity: " << points.capacity() << std::endl; // capacity: 0
    
    return EXIT_SUCCESS;
}