c++ 判断list是否为空（empty）

#include <list>
#include <iostream>
using namespace std;
int main()
{
    list<int> numbers;
    cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';

    numbers.push_back();
    numbers.push_back();
    cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';
}