std::queue

queue

成員函數

//initialize(1)
//explicit queue(const container_type& ctnr);
//move - initialize(2)
//explicit queue(container_type&& ctnr = container_type());
//allocator(3)
//template <class Alloc> explicit queue(const Alloc& alloc);
//init + allocator(4)
//template <class Alloc> queue(const container_type& ctnr, const Alloc& alloc);
//move - init + allocator(5)
//template <class Alloc> queue(container_type&& ctnr, const Alloc& alloc);
//copy + allocator(6)
//template <class Alloc> queue(const queue& x, const Alloc& alloc);
//move + allocator(7)
//template <class Alloc> queue(queue&& x, const Alloc& alloc);
#include<iostream>
#include<deque>
#include<queue>
#include<list>
using namespace std;
int main()
{
    deque<int> my_deque(3, 100);
    deque<int> my_list(2, 100);

    queue<int> first_queue;
    queue<int> second_queue(my_deque);
    queue<int,deque<int>> third_queue;
    queue<int,deque<int>> fourth_queue(my_list);

    cout << "size of first_queue: " << first_queue.size() << endl;
    cout << "size of second_queue: " << second_queue.size() << endl;
    cout << "size of third_queue: " << third_queue.size() << endl;
    cout << "size of fourth_queue: " << fourth_queue.size() << endl;

    return 0;
}

輸出
size of first_queue :0
size of second_queue :3
size of third_queue :0
size of fourth_queue :2

//bool empty() const;
//size_type size() const;
//void push(const value_type& val);
//void push(value_type&& val);
//reference& front();
//const_reference& front() const;
//reference& back();
//const_reference& back() const;
//template <class... Args> void emplace(Args&&... args);
//void swap(queue& x) noexcept(/*see below*/);
#include<iostream>
#include<queue>
#include<string>
using namespace std;
int main()
{
    queue<int> first_queue;
    if (first_queue.empty())
        cout << "first_queue is empty" << endl;
    for (int i = 1; i <= 5; i++)
        first_queue.push(i);
    cout << "first_queue's front :" << first_queue.front() << endl;
    cout << "first_queue's back :" << first_queue.back()<< endl;
    cout << "first_queue's size :" << first_queue.size() << endl;

    queue<string> second_queue;
    //emplace與push不同之處在於前者是構造然後插入，後者是插入
    second_queue.emplace("first_string");
    second_queue.emplace("second_string");
    while (!second_queue.empty())
    {
        std::cout << second_queue.front() << endl;
        second_queue.pop();
    }
    queue<int> third_queue;
    first_queue.swap(third_queue);
    cout << "third_queue's size :" << third_queue.size() << endl;
    return 0;
}

輸出：
first_queue is empty
first_queue’s front :1
first_queue’s back :5
first_queue’s size :5
first_string
second_string
third_queue’s size :5

priority_queue

成員函數

//initialize(1)
//priority_queue(const Compare& comp, const Container& ctnr);
//range(2)
//template <class InputIterator>
//priority_queue(InputIterator first, InputIterator last,
//  const Compare& comp, const Container& ctnr);
//move - initialize(3)
//explicit priority_queue(const Compare& comp = Compare(),
//  Container&& ctnr = Container());
//move - range(4)
//template <class InputIterator>
//priority_queue(InputIterator first, InputIterator last,
//  const Compare& comp, Container&& ctnr = Container());
//allocator versions(5)
//template <class Alloc> explicit priority_queue(const Alloc& alloc);
//template <class Alloc> priority_queue(const Compare& comp, const Alloc& alloc);
//template <class Alloc> priority_queue(const Compare& comp, const Container& ctnr,
//  const Alloc& alloc);
//template <class Alloc> priority_queue(const Compare& comp, Container&& ctnr,
//  const Alloc& alloc);
//template <class Alloc> priority_queue(const priority_queue& x, const Alloc& alloc);
//template <class Alloc> priority_queue(priority_queue&& x, const Alloc& alloc);
//bool empty() const;
//size_type size() const;
//const_reference top() const;
//void push(const value_type& val);
//void push(value_type&& val);
//template <class... Args> void emplace(Args&&... args);
//void swap(priority_queue& x) noexcept (/*see below*/);
#include<iostream>
#include<queue>
#include<vector>
#include<functional>
#include<string>
using namespace std;
class comparsion {
private:    bool reverse;
public:
    comparsion(const bool& revparam=false)
    {
        reverse = revparam;
    }
    bool operator()(const int& lhs,const int& rhs)const
    {
        if (reverse)
            return lhs > rhs;
        return lhs < rhs;
    }
};
int main()
{
    int ints []= { 10,30,20,40 };
    priority_queue<int> first_pq;
    priority_queue<int> second_pq(ints,ints+4);
    priority_queue<int, vector<int>, greater<int>> third_pq(ints, ints + 4);
    priority_queue<int, vector<int>, comparsion> fourth_pq(ints, ints + 4);
    priority_queue<int, vector<int>, comparsion> fifth_pq(comparsion(true));
    priority_queue<string> string_pq;
    string_pq.push("b");
    string_pq.push("a");
    string_pq.push("c");
    cout << "first_pq's size is " << first_pq.size() << endl;
    cout << "second_pq's size is " << second_pq.size() << endl;
    for (int i = 0; i != 4; i++)
        fifth_pq.push(ints[i]);
    while (!second_pq.empty())
    {
        cout << second_pq.top()<<" ";
        second_pq.pop();
    }
    cout << endl;
    while (!third_pq.empty())
    {
        cout << third_pq.top() << " ";
        third_pq.pop();
    }
    cout << endl;
    while (!fourth_pq.empty())
    {
        cout << fourth_pq.top() << " ";
        fourth_pq.pop();
    }
    cout << endl;
    while (!fifth_pq.empty())
    {
        cout << fifth_pq.top() << " ";
        fifth_pq.pop();
    }
    cout << endl;
    while (!string_pq.empty())
    {
        cout << string_pq.top() << " ";
        string_pq.pop();
    }
    cout << endl;
    return 0;
}

輸出：
first_pq’s size is 0
first_pq’s size is 4
40 30 20 10
10 20 30 40
40 30 20 10
10 20 30 40
c b a