STL_初识基本操作_vector_笔记

STL中最常用的容器为vector，可以理解为数组，通过该容器，初识STL

vector存放内置数据类型

容器：​​vector​​​算法：​​for_each​​迭代器：​​vector<int>::iterator​​

#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>//标准算法头文件
void myPrint(int val)
{
  cout << val << endl;
}
int main()
{
  //创建一个vector容器，数组
  vector<int> v;
  //向容器中插入数据
  v.push_back(10);
  v.push_back(20);
  v.push_back(30);
  v.push_back(40);
  //通过迭代器访问容器中的数据
  //起始迭代器，指向容器中第一个元素
  vector<int>::iterator itBegin = v.begin();
  //结束迭代器，指向容器中最后一个元素的下一个位置
  vector<int>::iterator itEnd = v.end();
  //第一种遍历方式
  while (itBegin != itEnd)
  {
    cout << *itBegin << endl;
    itBegin++;
  }
  //第二种遍历
  for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
  {
    cout << *it << endl;
  }
  //第三种遍历，利用STL提供的遍历算法
  for_each(v.begin(), v.end(), myPrint);
  return 0;
}

vector存放自定义数据类型

​​vector<Person*>::iterator it​​​中​​*it​​​是​​Person*​​

#include<iostream>
using namespace std;
#include<string>
#include<vector>
#include<algorithm>
class Person
{
public:
  string m_name;
  int m_age;
  Person(string name, int age)
  {
    this->m_name = name;
    this->m_age = age;
  }
};
int main()
{
  vector<Person>v;
  Person p1("A", 1);
  Person p2("B", 2);
  Person p3("C", 3);
  v.push_back(p1);
  v.push_back(p2);
  v.push_back(p3);
  for (vector<Person>::iterator it = v.begin(); it != v.end(); it++)
  {
    cout << (*it).m_name << (*it).m_age << endl;
  }
  return 0;
}

vector<Person*>v;
  Person p1("A", 1);
  Person p2("B", 2);
  Person p3("C", 3);
  v.push_back(&p1);
  v.push_back(&p2);
  v.push_back(&p3);
  for (vector<Person*>::iterator it = v.begin(); it != v.end(); it++)
  {
    cout << (*(*it)).m_name << (*(*it)).m_age << endl;
  }

vector容器嵌套容器

#include<iostream>
using namespace std;
#include<string>
#include<vector>
#include<algorithm>
class Person
{
public:
  string m_name;
  int m_age;
  Person(string name, int age)
  {
    this->m_name = name;
    this->m_age = age;
  }
};
int main()
{
  vector<vector<int>> v;
  vector<int> v1;
  vector<int> v2;
  vector<int> v3;
  vector<int> v4;
  //向小容器中添加数据
  for (int i = 0; i < 4; i++)
  {
    v1.push_back(i);
    v2.push_back(i + 1);
    v3.push_back(i + 2);
    v4.push_back(i + 3);
  }
  //将小容器添加到大容器中
  v.push_back(v1);
  v.push_back(v2);
  v.push_back(v3);
  v.push_back(v4);
  //通过大容器，把所有数据遍历一遍
  for (vector<vector<int>>::iterator it = v.begin(); it != v.end(); it++)
  {
    for (vector<int>::iterator vit = (*it).begin(); vit != (*it).end(); vit++)
    {
      cout << *vit << " ";
    }
    cout << endl;
  }
  return 0;
}