unordered_set

#include <iostream>
#include <unordered_set>
int main()
{
        std::unordered_set<int> X { 2020, 2019, 2018 };
        X.insert(19);
        X.insert(99);
        X.insert(89);
        X.insert(59);
        X.insert(79);
        for (auto Y: X)
                std::cout << Y << '
';
        return 0;
}

root@ubuntu:~/c++# ./set
79
59
89
99
2020
2019
19
2018

#include <iostream>
#include <unordered_set>
int main()
{
std::unordered_set<int> X { 2020, 2019, 2018 };
for (auto Y: X)
std::cout << Y << '
';
return 0;
}

root@ubuntu:~/c++# g++ -std=c++11  set.cpp -o set
root@ubuntu:~/c++# ./set
2018
2019
2020

#include <iostream>
#include <set>
int main()
{
        std::set<int> X { 2020, 2019, 2018 };
        for (auto Y: X)
                std::cout << Y << '
';
        return 0;
}

有序输出

root@ubuntu:~/c++# g++ -std=c++11  set.cpp -o set
root@ubuntu:~/c++# ./set
2018
2019
2020

#include <iostream>
#include <set>
int main()
{
        std::set<int> X { 2020, 2019, 2018 };
        X.insert(2019);
        for (auto Y: X)
                std::cout << Y << '
';
        return 0;
}

没有重复数据

root@ubuntu:~/c++# g++ -std=c++11  set.cpp -o set
root@ubuntu:~/c++# ./set
2018
2019
2020

#include <iostream>
#include <set>
int main()
{
        std::set<int> X { 2020, 2019, 2018 };
        X.insert(19);
        X.insert(99);
        X.insert(89);
        X.insert(59);
        X.insert(79);
        for (auto Y: X)
                std::cout << Y << '
';
        return 0;
}

root@ubuntu:~/c++# g++ -std=c++11  set.cpp -o set
root@ubuntu:~/c++# ./set
19
59
79
89
99
2018
2019
2020

~