std::forward_list

成員函數

//函數簽名
//default (1)
//explicit forward_list(const allocator_type& alloc = allocator_type());
//fill(2)
//explicit forward_list(size_type n);
//explicit forward_list(size_type n, const value_type& val,
//  const allocator_type& alloc = allocator_type());
//range(3)
//template <class InputIterator>
//forward_list(InputIterator first, InputIterator last,
//  const allocator_type& alloc = allocator_type());
//copy(4)
//forward_list(const forward_list& fwdlst);
//forward_list(const forward_list& fwdlst, const allocator_type& alloc);
//move(5)
//forward_list(forward_list&& fwdlst);
//forward_list(forward_list&& fwdlst, const allocator_type& alloc);
//initializer list(6)
//forward_list(initializer_list<value_type> il,
//  const allocator_type& alloc = allocator_type());
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int> first_fl;
    forward_list<int> second_sl(8, 11);
    forward_list<int> third_sl(second_sl.begin(), second_sl.end());
    forward_list<int> fourth_sl(third_sl);
    forward_list<int> fifth_sl(move(fourth_sl));    //將fourth_sl的元素移至fifth_sl
    forward_list<int> sixth_sl = { 0,8,11 };
    cout << "first_fl:"; for (const int &x : first_fl) cout << x << " "; cout << endl;
    cout << "second_sl:"; for (const int &x : second_sl) cout << x << " "; cout << endl;
    cout << "third_sl:"; for (const int &x : third_sl) cout << x << " "; cout << endl;
    cout << "fourth_sl:"; for (const int &x : fourth_sl) cout << x << " "; cout << endl;
    cout << "fifth_sl:"; for (const int &x : fifth_sl) cout << x << " "; cout << endl;
    cout << "sixth_sl:"; for (const int &x : sixth_sl) cout << x << " "; cout << endl;
    return 0;
}

輸出：
first_sl:
second_sl:11 11 11 11 11 11 11 11
third_sl:11 11 11 11 11 11 11 11
fourth_sl:
fifth_sl:11 11 11 11 11 11 11 11
sixth_sl:0 8 11

//函數簽名
//copy(1)
//forward_list& operator= (const forward_list& fwdlst);
//move(2)
//forward_list& operator= (forward_list&& fwdlst);
//initializer list(3)
//forward_list& operator= (initializer_list<value_type> il);
#include<iostream>
#include<forward_list>
using namespace std;
template<class T>
T by_two(const T& x)
{
    T temp(x);
    for (int& y : temp)
        y *= 2;
    return temp;
}
int main()
{
    forward_list<int> first_fl(4);
    forward_list<int> second_fl(3, 5);

    first_fl = second_fl;       //copy assignment function 被調用,這裏second_fl是lvalue
    second_fl = by_two(first_fl);       //move assignment function 被調用,by_two返回的值爲rvalue

    cout << "first_fl:"; for (const int& x : first_fl) cout << x << " "; cout << endl;
    cout << "second_fl:"; for (const int& x : second_fl) cout << x << " "; cout << endl;
    return 0;
}

輸出：
first_sl:5 5 5
second_sl:10 10 10

Iterators

//函數簽名
//iterator before_begin() noexcept;
//const_iterator before_begin() const noexcept;
//iterator begin() noexcept;
//const_iterator begin() const noexcept;
//iterator end() noexcept;
//const_iterator end() const noexcept;
//const_iterator cbefore_begin() const noexcept;
//const_iterator cbegin() const noexcept;
//const_iterator cend() const noexcept;
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int> first_sl = { 20,30,40,50 };
    first_sl.insert_after(first_sl.before_begin(), 10);   
    for (auto it = first_sl.begin(); it != first_sl.end(); it++)
        cout << *it << " ";
    cout << endl;

    //cbefore_begin返回一個迭代器，該迭代器指向一個常數，該迭代器本身可以移動（除非該迭代器本身爲const）
    first_sl.insert_after(first_sl.cbefore_begin(), 0);    
    for (auto it = first_sl.cbegin(); it != first_sl.cend();it++)
        cout << *it << " ";
    cout << endl;
    return 0;
}

輸出：
10 20 30 40 50
0 10 20 30 40 50

Capacity

//函數簽名
//bool empty() const noexcept;
//size_type max_size () const noexcept;
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int> first_sl = { 0,8,11 };
    if (first_sl.empty())
        cout << "empty" << endl;
    else
        cout << "not empty" << endl;
    //max_size取決於系統以及庫的實現
    cout << "first_sl max_size is :" << first_sl.max_size() << endl;
    return 0;
}

輸出：
not empty
first_sl max_size is :536870911

Element access

//函數簽名 
//reference front();
//const_reference front() const;
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int> first_sl = { 0,8,11 };
    first_sl.front() = 99;
    for (const int& x : first_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
99 8 11

Modifiers

//函數簽名
//range(1)
//template <class InputIterator>
//void assign(InputIterator first, InputIterator last);
//fill(2)
//void assign(size_type n, const value_type& val);
//initializer list(3)
//void assign(initializer_list<value_type> il);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    //使用assign 取代當前的內容並且修改其大小
    forward_list<int> first_sl = { 0,8,11 };
    forward_list<int> second_sl;
    forward_list<int> third_sl;
    forward_list<int> fourth_sl ;

    second_sl.assign(first_sl.begin(), first_sl.end());
    third_sl.assign(3, 1);
    fourth_sl.assign({2,3,4});
    cout << "first_sl:"; for (const int& x : first_sl) cout << x << " "; cout << endl;
    cout << "second_sl:"; for (const int& x : second_sl) cout << x << " "; cout << endl;
    cout << "third_sl:"; for (const int& x : third_sl) cout << x << " "; cout << endl;
    cout << "fourth_sl:"; for (const int& x : fourth_sl) cout << x << " "; cout << endl;

    return 0;
}

輸出：
first_sl:0 8 11
second_sl:0 8 11
third_sl:1 1 1
fourth_sl:2 3 4

//函數簽名
//template <class... Args>
//void emplace_front(Args&&... args);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    //在forward_list的起始位置插入一個新值
    forward_list<pair<int,char> > first_sl;
    first_sl.emplace_front(1, 'a');
    first_sl.emplace_front(2, 'b');
    first_sl.emplace_front(3,'c');
    for (const auto& x : first_sl)
        cout << x.first << " " << x.second << endl;
    cout << endl;
    return 0;
}

輸出：
3 c
2 b
1 a

//函數簽名
//void push_front(const value_type& vakl);
//void push_front(value_type&& val);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    //在forward_list的起始位置插入一個新值,注意和emplace_front的區別（看函數簽名）
    forward_list<pair<int, char> > first_sl;
    first_sl.push_front(make_pair(2, 'a'));
    first_sl.push_front(make_pair(4, 'b'));
    first_sl.push_front(make_pair(6, 'c'));
    for (const auto& x : first_sl)
        cout << x.first << " " << x.second << endl;
    cout << endl;
    return 0;
}

輸出：
6 c
4 b
2 a

//函數簽名
//void pop_front();
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    //在forward_list的起始位置插入一個新值,注意和emplace_front的區別（看函數簽名）
    forward_list<int > first_sl = { 1,2,3 };
    while (!first_sl.empty())
    {
        cout << first_sl.front() << endl;
        first_sl.pop_front();
    }
    cout << endl;
    return 0;
}

輸出：
1
2
3

//函數簽名
//template <class... Args>
//iterator emplace_after(const_iterator position, Args&&... args);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 2,4,6 };
    first_sl.emplace_after(first_sl.begin(), 3);
    first_sl.emplace_after(first_sl.begin(), 5);
    for (const int&x : first_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
2 5 3 4 6

//函數簽名
//(1)iterator insert_after(const_iterator position, const value_type& val);
//(2)iterator insert_after(const_iterator position, value_type&& val);
//(3)iterator insert_after(const_iterator position, size_type n, const value_type& val);
//(4)template <class InputIterator>
//iterator insert_after(const_iterator position, InputIterator first, InputIterator last);
//(5)iterator insert_after(const_iterator position, initializer_list<value_type> il);
#include<iostream>
#include<forward_list>
#include<array>
using namespace std;
int main()
{
    array<int, 3> first_array = {1,2,3};
    forward_list<int > first_sl = { 2,4,6 };
    forward_list<int>::iterator it;
    it = first_sl.insert_after(first_sl.begin(), 0);    //現在it指向0
    it = first_sl.insert_after(it, 2, 4);               //現在it指向第二個4
    it = first_sl.insert_after(it, first_array.begin(), first_array.end());   //現在it指向3
    first_sl.insert_after(first_sl.begin(), { 0,0,0 });
    for (const int&x : first_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
2 0 0 0 0 4 4 1 2 3 4 6

//函數簽名
//iterator erase_after(const_iterator position);
//iterator erase_after(const_iterator position, const_iterator last);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3,4,5 };
    auto it = first_sl.begin();
    it = first_sl.erase_after(it);  //刪除2，現在it指向3
    first_sl.erase_after(it, first_sl.end());
    for (const int&x : first_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
1 3

//函數簽名
//void swap(forward_list& fwdlst);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3 };
    forward_list<int > second_sl = { 4,5,6 };
    first_sl.swap(second_sl);
    for (const int&x : first_sl)
        cout << x << " ";
    cout << endl;
    for (const int&x : second_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
4 5 6
1 2 3

//函數簽名
//void resize(size_type n);
//void resize(size_type n, const value_type& val);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3,4,5 };
    first_sl.resize(3);//現在first_sl爲 1 2 3
    first_sl.resize(5, 0);//現在first_sl爲1 2 3 0 0
    for (const int&x : first_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
1 2 3 0 0

//函數簽名
//void clear() noexcept;
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3,4,5 };
    first_sl.clear();
    if (first_sl.empty())
        cout << "empty" << endl;
    else
        cout << "not empty" << endl;
    return 0;
}

輸出：
empty

Operations

//函數簽名
//entire list(1)
//void splice_after(const_iterator position, forward_list& fwdlst);
//void splice_after(const_iterator position, forward_list&& fwdlst);
//single element(2)
//void splice_after(const_iterator position, forward_list& fwdlst, const_iterator i);
//void splice_after(const_iterator position, forward_list&& fwdlst, const_iterator i);
//element range(3)
//void splice_after(const_iterator position, forward_list& fwdlst,
//  const_iterator first, const_iterator last);
//void splice_after(const_iterator position, forward_list&& fwdlst,
//  const_iterator first, const_iterator last);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3 };
    forward_list<int > second_sl = { 4,5,6 };
    auto it = first_sl.begin();
    //first_sl：4 5 6 1 2 3    second_sl：
    first_sl.splice_after(first_sl.before_begin(), second_sl);  
    //first_sl：4 1 2 3    second_sl：5 6 
    second_sl.splice_after(second_sl.before_begin(), first_sl, first_sl.begin(), it);
    //first_sl：6 4 1 2 3  second_sl：5
    first_sl.splice_after(first_sl.before_begin(), second_sl, second_sl.begin());

    for (const auto& x : first_sl)cout << x << " ";
    cout << endl;
    for (const auto& x : second_sl)cout << x << " ";
    cout << endl;

    return 0;
}

輸出：
6 4 1 2 3
5

//函數簽名
//void remove(const value_type& val);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3,4,5,5,4,3,2,1 };
    first_sl.remove(4);
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
1 2 3 5 5 3 2 1

//函數簽名
//template <class Predicate>
//void remove_if(Predicate pred);
#include<iostream>
#include<forward_list>
using namespace std;

bool single_digit(const int & value)
{
    return value < 10;
}
class is_old 
{
public:
    bool operator() (const int& value)
    {
        return (value % 2) == 1;
    }
};
int main()
{
    forward_list<int > first_sl = { 1,2,3,4,5,11,22,33,44,55 };
    first_sl.remove_if(single_digit);       //傳一個方法
    first_sl.remove_if(is_old());       //傳一個對象，該對象實現了()操作符
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
22 44

//函數簽名
//(1)void unique();
//(2)template <class BinaryPredicate>
//void unique(BinaryPredicate binary_pred);
#include<iostream>
#include<forward_list>
#include<algorithm>
using namespace std;

bool same_int(const double& a, const double &b)
{
    return (int)a == (int)b;
}
class is_near 
{
public:
    bool operator()(const double& a, const double & b)
    {
        return abs(a - b) < 3;
    }
};

int main()
{
    forward_list<double > first_sl = { 1.1,2.2,2.4,2.2,4,5,1.1,2.2,3.3,15.5,8.5 };
    //unique函數只會刪除相鄰相同的元素，如果該鏈表未排序，使用意義不大
    first_sl.sort();
    first_sl.unique();      //刪除相同元素
    first_sl.unique(same_int);      //刪除整數相同的元素
    first_sl.unique(is_near());     //刪除插值小於3的元素
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
1.1 5 8.5 15.5

//函數簽名
//(1)void merge(forward_list& fwdlst);
//void merge(forward_list&& fwdlst);
//(2)template <class Compare>
//void merge(forward_list& fwdlst, Compare comp);
//template <class Compare>
//void merge(forward_list&& fwdlst, Compare comp);
#include<iostream>
#include<forward_list>
#include<functional>
using namespace std;
int main()
{
    forward_list<double > first_sl = { 1,3,5 };
    forward_list<double > second_sl = { 2,4,6 };
    forward_list<double > third_sl = { 6 ,8, 10};
    first_sl.merge(second_sl);      //合併兩個forward_list,兩個forward_list必須都是有序的，second_sl的元素被移至first_sl
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    first_sl.sort(greater<double>());
    third_sl.sort(greater<double>());
    third_sl.merge(first_sl,greater<double>());         //傳一個函數對象
    for each (auto var in third_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
1 2 3 4 5 6
10 8 6 6 5 4 3 2 1

//函數簽名
//(1)void sort();
//(2)template <class Compare>
//void sort(Compare comp);
#include<iostream>
#include<forward_list>
#include<functional>
using namespace std;
int main()
{
    forward_list<double > first_sl = { 2,4,6,1,3,5 };
    first_sl.sort();
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    first_sl.sort(greater<double>());
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
1 2 3 4 5 6
6 5 4 3 2 1

//函數簽名
//void reverse() noexcept;
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3 };
    first_sl.reverse();     //逆置forward_list
    for each (auto var in first_sl)
    {
        cout << var << " ";
    }
    cout << endl;
    return 0;
}

輸出：
3 2 1

非成員函數

//函數簽名
//(1)
//template <class T, class Alloc>
//bool operator== (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
//(2)
//template <class T, class Alloc>
//bool operator!= (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
//(3)
//template <class T, class Alloc>
//bool operator<  (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
//(4)
//template <class T, class Alloc>
//bool operator<= (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
//(5)
//template <class T, class Alloc>
//bool operator>  (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
//(6)
//template <class T, class Alloc>
//bool operator>= (const forward_list<T, Alloc>& lhs, const forward_list<T, Alloc>& rhs);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3 };
    forward_list<int > second_sl = { 1,2,3 };
    forward_list<int > third_sl = { 1,1,4 };
    if (first_sl == second_sl)
        cout << "first_sl==second_sl" << endl;
    if (first_sl != second_sl)
        cout << "first_sl!=second_sl" << endl;
    if(second_sl>=third_sl)
        cout << "second_sl>=third_sl" << endl;
    if(second_sl <= third_sl)
        cout << "second_sl<=third_sl" << endl;
    return 0;
}

輸出：
first_sl==second_sl
second_sl<=third_sl

//函數簽名
//template <class T, class Alloc>
//void swap(forward_list<T, Alloc>& x, forward_list<T, Alloc>& y);
#include<iostream>
#include<forward_list>
using namespace std;
int main()
{
    forward_list<int > first_sl = { 1,2,3 };
    forward_list<int > second_sl = { 3,2,1 };
    swap(first_sl, second_sl);
    for (const auto& x : first_sl)
        cout << x << " ";
    cout << endl;
    for (const auto& x : second_sl)
        cout << x << " ";
    cout << endl;
    return 0;
}

輸出：
3 2 1
1 2 3