vector清空内存的2种方法

最新推荐文章于 2025-03-27 14:13:48 发布

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最新推荐文章于 2025-03-27 14:13:48 发布

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本文通过C++代码示例，深入探讨了std::vector容器的capacity(容量)和size(大小)属性，包括它们在不同操作（如clear、swap、push_back和shrink_to_fit）后的变化，揭示了vector内部内存管理机制。

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#include <iostream>
#include <vector>
using namespace std;
int main()
{
        vector<int> myvector;
        for (int i = 0; i < 100; i++)
    {
                myvector.push_back(i);
            
    }
        cout << "capacity值为："<<myvector.capacity() << endl;
        cout << "size值为：" << myvector.size() << endl;
        myvector.clear();
        cout << "clear之后...." << endl;
        cout << "capacity值为：" << myvector.capacity() << endl;
        cout << "size值为：" << myvector.size() << endl;
        vector<int>().swap(myvector);
        cout << "swap操作后..." << endl;
        cout << "capacity值为：" << myvector.capacity() << endl;
        cout << "size值为：" << myvector.size() << endl;
        for (int i = 0; i < 100; i++)
   		 {
                myvector.push_back(i);
            
   		 }
        cout << "重新push_back后...." << endl;
        cout << "capacity值为：" << myvector.capacity() << endl;
        cout << "size值为：" << myvector.size() << endl;
        myvector.clear();
        myvector.shrink_to_fit();
        cout << "clear+ shrink_to_fit()后..." << endl;
        cout << "capacity值为：" << myvector.capacity() << endl;
        cout << "size值为：" << myvector.size() << endl;
        cin.get();
        system("pause");
        return 0;

}