2.set大小和交换

#include<iostream>
using namespace std;

#include<set>

void printSet(set<int> st)
{
    for (set<int>::const_iterator it = st.begin(); it != st.end(); it++)
    {
        cout << (*it) << " ";
    }
    cout << endl;
}
void test0201()
{
    set<int> s1;

    s1.insert(10);
    s1.insert(20);
    s1.insert(30);
    s1.insert(40);

    printSet(s1);

    if (s1.empty())
    {
        cout << "s1为空" << endl;
    }
    else
    {
        cout << "s1不为空" << endl;
        cout << "s1大小：" << s1.size() << endl;
    }

    set<int> s2;

    s2.insert(1098);
    s2.insert(5000);
    s2.insert(30897);
    s2.insert(40689);

    cout << "交换前：" << endl;
    printSet(s1);
    printSet(s2);

    cout << "交换后：" << endl;
    s1.swap(s2);
    printSet(s1);
    printSet(s2);
}

int main()
{
    test0201();

    system("pause");
    return 0;
}