1、std::vector::push_back（尾差）

1.1、std::vector::operator[]

意思为；
访问元素
返回对vector容器中位置n的元素的引用。

void test_vector2()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(2);
	v1.push_back(3);
	v1.push_back(4);

	//下标+[]
	for (size_t i = 0; i < v1.size(); i++)
	{
		v1[i]++;
	}

	for (size_t i = 0; i < v1.size(); i++)
	{
		cout << v1[i] << " ";
	}
	cout << endl;
}

int main()
{
	//test_vector1();
	test_vector2();
	return 0;
}

2、vector迭代器

vector也是支持迭代器的，其功能和string迭代器是一样的

void test_vector2()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(2);
	v1.push_back(3);
	v1.push_back(4);

	//下标+[]
	for (size_t i = 0; i < v1.size(); i++)
	{
		v1[i]++;
	}

	for (size_t i = 0; i < v1.size(); i++)
	{
		cout << v1[i] << " ";
	}
	cout << endl;

	//迭代器
	vector<int>::iterator it = v1.begin();
	while (it != v1.end())
	{
		(*it)--;
		cout << *it <<" ";
		it++;
	}
	cout << endl;
	
	for (auto e : v1)
	{
		cout << e << " ";
	}
}

int main()
{
	//test_vector1();
	test_vector2();
	return 0;
}

2.1、std::find

注意是左闭右开的，如果没有找到会返回last

2.2、std::vector::insert（插入）

vector和string的insert插入的直接区别就是vector的插入坐标位置都是通过迭代器iterator来控制的

void test_vector3()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(2);
	v1.push_back(3);
	v1.push_back(4);

	for (size_t i = 0; i < v1.size(); i++)
	{
		cout << v1[i] << " ";
	}
	cout << endl;

	vector<int>::iterator pos = find(v1.begin(), v1.end(), 3);

	if (pos != v1.end())//因为如果查找失败返回的是v1.end()
	{
		v1.insert(pos, 30);
	}
	
	for (auto e : v1)
	{
		cout << e << " ";
	}

	cout << endl;
}


int main()
{
	//test_vector1();
	test_vector3();
	return 0;
}

如果在find查找完后没有进行if判断，这是如果没有找到对应的元素就会变为尾插，但是我们建议还是加上判断条件的

3、std::vector::erase（删除）

void test_vector3()
{
	vector<int> v1;
	v1.push_back(1);
	v1.push_back(2);
	v1.push_back(3);
	v1.push_back(4);

	for (size_t i = 0; i < v1.size(); i++)
	{
		cout << v1[i] << " ";
	}
	cout << endl;

	vector<int>::iterator pos = find(v1.begin(), v1.end(), 3);

	if (pos != v1.end())//因为如果查找失败返回的是v1.end()
	{
		//v1.insert(pos, 30);
		v1.erase(pos);
	}
	
	for (auto e : v1)
	{
		cout << e << " ";
	}

	cout << endl;
}


int main()
{
	//test_vector1();
	test_vector3();
	return 0;
}

4、std::sort（排序）

使用sort时，需要先包含头文件#include <algorithm>

排序默认为从小到大排列，如果想从大到小排列需要包含头文件

void test_vector4()
{
	vector<int> v1;
	v1.push_back(10);
	v1.push_back(1);
	v1.push_back(32);
	v1.push_back(12);
	v1.push_back(2);
	v1.push_back(4);
	v1.push_back(5);

	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;

	less<int> ls;
	sort(v1.begin(), v1.end(),ls);
	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;

	sort(v1.begin(), v1.end());
	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;
}

int main()
{
	//test_vector1();
	test_vector4();
	return 0;
}

如果想要从大到小排列，需要包含头文件#include <functional>

void test_vector4()
{
	vector<int> v1;
	v1.push_back(10);
	v1.push_back(1);
	v1.push_back(32);
	v1.push_back(12);
	v1.push_back(2);
	v1.push_back(4);
	v1.push_back(5);

	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;

	less<int> ls;
	sort(v1.begin(), v1.end(),ls);
	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;

	sort(v1.begin(), v1.end());
	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;

	greater<int> gt;

	sort(v1.begin(), v1.end(),gt);
	//定义匿名方式
	//sort(v1.begin(), v1.end(),greater<int>());
	for (auto e : v1)
	{
		cout << e << " ";
	}
	cout << endl;
}

int main()
{
	//test_vector1();
	test_vector4();
	return 0;
}

sort不仅可以排序动态容器vector，还可以排序字符串

void test_vector5()
{
	string s1("hello1234");
	sort(s1.begin(), s1.end(), greater<char>());
	cout << s1 << " ";
	cout << endl;
}

int main()
{
	//test_vector1();
	test_vector5();
	return 0;
}