set 自定义比较函数

set 自定义比较函数

set的底层为红黑树

/*
 * @Author       : Hi_Wind
 * @Date         : 2022-10-26 08:26:49
 * @LastEditTime : 2022-10-26 08:33:16
 * @FilePath     : \text\text_set.cpp
 */
#include 

using namespace std;

#include 

class Heroes
{
public:
    Heroes(string _name, int _age) : name(_name), age(_age) {}
    friend class exCmp;
    friend ostream &operator<<(ostream &O, const Heroes &os);

private:
    string name;
    int age;
};
//重载 << 操作符，让其直接输出 Heroes 对象信息
ostream &operator<<(ostream &O, const Heroes &os)
{
    O << " " << os.name << "  " << os.age;
    return O;
}

// 定义外部比较器
class exCmp
{
public:
    bool operator()(const Heroes &a, const Heroes &b) const
    {
        return a.age > b.age; // 按照年龄从大到小进行存放
    }
};

int main()
{
    set<Heroes, exCmp> hero;
    hero.insert({"aa", 30});
    hero.insert({"bb", 29});
    hero.insert({"cc", 34});

    for (auto &it : hero)
    {
        cout << it << endl;
    }
    return 0;
}

结果：