#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl1;//default
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//空

	forward_list<int> fl2(10, 1);//fill
	for (auto e : fl2)
	{
		cout << e << " ";
	}
	cout << endl;
	//1 1 1 1 1 1 1 1 1 1

	string s("hello world");
	forward_list<char> fl3(s.begin() + 3, --s.end());//range
	for (auto e : fl3)
	{
		cout << e << " ";
	}
	cout << endl;
	//l o   w o r l

	forward_list<char> fl4(fl3);//copy
	//等价于forward_list<char> fl4 = fl3;
	for (auto e : fl4)
	{
		cout << e << " ";
	}
	cout << endl;
	//l o   w o r l

	forward_list<int> fl5{ 2,4,6,8 };//initializer list
	//等价于forward_list<int> fl5 = { 2,4,6,8 };
	for (auto e : fl5)
	{
		cout << e << " ";
	}
	cout << endl;
	//2 4 6 8

	return 0;
}

1.1.2 析构函数

1.1.3 赋值运算符重载

1.2 迭代器

before_begin&begin&end返回的迭代器指向：

const_iterator是一个指向const内容的迭代器。迭代器本身可以修改，但是它不能被用来修改它所指向的内容。

before_begin&begin&end和cbefore_begin&cbegin&cend的不同：

• before_begin&begin&end的返回类型由对象是否是常量来决定。如果不是常量，返回iterator；如果是常量，返回const_iterator。
• cbefore_begin&cbegin&cend的返回类型是const_iterator，不管对象本身是否是常量。

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl{ 4,5,6,7 };
	fl.insert_after(fl.before_begin(), 3);
	for (auto e : fl)
	{
		cout << e << " ";
	}
	cout << endl;
	//3 4 5 6 7

	forward_list<int>::iterator it = fl.begin();
	while (it != fl.end())
	{
		cout << *it << " ";
		++it;
	}
	cout << endl;
	//3 4 5 6 7

	return 0;
}

1.3 容量

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl{ 4,5,6,7 };

	if (fl.empty())
		cout << "forward_list为空" << endl;
	else
		cout << "forward_list不为空" << endl;
	//forward_list不为空

	cout << fl.max_size() << endl;//536870911

	return 0;
}

1.4 元素访问

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl{ 4,5,6,7 };

	cout << fl.front() << endl;//4

	return 0;
}

1.4.1 遍历方法

1.4.1.1 迭代器

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl{ 4,5,6,7 };

	forward_list<int>::iterator it = fl.begin();
	while (it != fl.end())
	{
		cout << *it << " ";
		++it;
	}
	cout << endl;
	//4 5 6 7

	return 0;
}

1.4.1.2 范围for

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl{ 4,5,6,7 };

	for (auto e : fl)
	{
		cout << e << " ";
	}
	cout << endl;
	//4 5 6 7

	return 0;
}

1.5 修改器

#include <iostream>
#include <forward_list>
#include <string>
using namespace std;

int main()
{
	forward_list<int> fl1{ 4,5,6,7 };

	fl1.assign({ 1,2,3,4,5,6 });
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//1 2 3 4 5 6

	fl1.push_front(0);
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//0 1 2 3 4 5 6

	fl1.pop_front();
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//1 2 3 4 5 6

	fl1.insert_after(fl1.before_begin(), 0);
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//0 1 2 3 4 5 6

	fl1.erase_after(fl1.begin());
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//0 2 3 4 5 6

	forward_list<int> fl2{ 4,5,6,7,8,9,10 };

	fl1.swap(fl2);
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//4 5 6 7 8 9 10

	fl1.resize(12, 5);
	for (auto e : fl1)
	{
		cout << e << " ";
	}
	cout << endl;
	//4 5 6 7 8 9 10 5 5 5 5 5

	fl1.clear();
	if (fl1.empty())
		cout << "fl1被清空" << endl;
	else
		cout << "fl1没被清空" << endl;
	//fl1被清空

	return 0;
}

1.6 操作

1.7 观察者

2. forward_list的非成员函数