C++学习笔记(字符串string、vector_deque、queue,multiset、map、multimap、容器拷贝问题)(复制粘贴,方便后面翻阅)

1.string操作

#include <iostream>
#include <string>
#include <algorithm> //算法

using namespace std;

//STL standard template libary 标准模(mu)板库 C++一部分，编译器自带
//Android NDK支持
//java.lang java.util包中API，java的一部分

//string初始化

void main()
{
//string由c字符串衍生过来的
string s1 = "craig david";
string s2("7 days");
string s3 = s2;
string s4(10,'a');

cout << s4 << endl;

system("pause");
}

//string遍历
void main()
{
string s1 = "craig david";
//           ^
//1 数组方式
for (int i = 0; i < s1.length(); i++)
{
cout << s1[i] << endl;
}
//2 迭代器指针
for (string::iterator it = s1.begin(); it != s1.end(); it++)
{
cout << *it << " ";
}
cout << endl;
//3 at函数(charAt)
// 可能会抛出异常
try
{
for (int i = 0; i < s1.length() + 3; i++)
{
cout << s1.at(i) << " ";
}
}
catch (...)
{
cout << "异常" << endl;
}

system("pause");
}

//string字符串->c字符串转换
void main()
{
//string -> char*
string s1 = "walking away";
const char* c = s1.c_str();
printf("%s\n",c);

//
string s2 = c;

//string->char[]
//从string中赋值字符到char[]
char arr[50] = {0};
s1.copy(arr,4,0);

cout << arr << endl;

system("pause");
}

//字符串拼接
void main()
{
string s1 = "alan";
string s2 = "jackson";

//1.
string s3 = s1 + s2;

string s4 = " pray";

//2.
s3.append(s4);

cout << s3 << endl;

system("pause");
}

//字符串查找替换
void main()
{
string s1 = "apple google apple iphone";
//从0开始查找"google"的位置
int idx = s1.find("google", 0);
cout << idx << endl;

//统计apple出现的次数
int idx_app = s1.find("apple",0);
//npos大于任何有效下标的值
int num = 0;
while (idx_app != string::npos)
{
num++;
cout << "找到的索引:" << idx_app << endl;
idx_app+=5;
idx_app = s1.find("apple", idx_app);
}

cout << num << endl;
system("pause");
}

void main()
{
string s1 = "apple google apple iphone";
//0-5（不包含5）替换为jobs
s1.replace(0, 5, "jobs");
cout << s1 << endl;

//所有apple替换为jobs
int idx = s1.find("apple", 0);
while (idx != string::npos)
{
s1.replace(idx, 5, "jobs");
idx += 5;
idx = s1.find("apple", idx);
}

cout << s1 << endl;
system("pause");
}

//删除（截取）和插入
void main()
{
string s1 = "apple google apple iphone";
//删除a，找到a所在的指针
string::iterator it = find(s1.begin(),s1.end(),'g');
//只能删除一个字符
s1.erase(it);

//开头末尾插入字符串
s1.insert(0, "macos");
s1.insert(s1.length(), " facebook");

cout << s1 << endl;
system("pause");
}

//java StringBuffer才可变
//String 不可变
//大小写转换
void main()
{
string s1 = "JASON";
//原始字符串的起始地址，原始字符串的结束地址, 目标字符串的起始地址, 函数名称
transform(s1.begin(), s1.end()-1,s1.begin(), tolower);
cout << s1 << endl;

transform(s1.begin(), s1.end() - 1, s1.begin(), toupper);
cout << s1 << endl;

system("pause");
}

2.容器vector

//容器
//Vector
//初始化
#include <vector>
void printVector(vector<int> &v)
{
//通过数组的方式遍历
for (int i = 0; i < v.size(); i++)
{
cout << v[i] << endl;
}
}
void main()
{
//1.
vector<int> v1;
v1.push_back(20);
v1.push_back(40);
v1.push_back(15);
v1.push_back(7);

//2.
vector<int> v2 = v1;

//3.部分复制
vector<int> v3(v1.begin(),v1.begin()+2);

printVector(v3);

system("pause");
}

//添加 删除
void main()
{
//添加到结尾
vector<int> v1;
v1.push_back(20);
v1.push_back(40);
v1.push_back(15);
v1.push_back(7);

//访问头部
v1.front() = 11;
//访问尾部
v1.back() = 90;

//删除结尾的元素
//v1.pop_back();
while (v1.size() > 0)
{
cout << "末尾的元素：" << v1.back() << endl;
v1.pop_back();
}

printVector(v1);

system("pause");
}

//数组的方式
void main()
{
vector<int> v1;
v1.push_back(20);
v1.push_back(40);
v1.push_back(15);
v1.push_back(7);

v1[2] = v1[2] +10;

//容器等价于动态数组
vector<int> v2(10);
for (int i = 0; i < v2.size(); i++)
{
v2[i] = i + 1;
}

printVector(v2);

system("pause");
}

//迭代器遍历
//迭代器的种类（正向，反向迭代器）
void main()
{
vector<int> v1;
v1.push_back(20);
v1.push_back(40);
v1.push_back(15);
v1.push_back(7);
//正向
for (vector<int>::iterator it = v1.begin(); it < v1.end(); it++)
{
cout << *it << endl;
}
cout << "-----------------" << endl;
//反向迭代
for (vector<int>::reverse_iterator it = v1.rbegin(); it < v1.rend(); it++)
{
cout << *it << endl;
}

system("pause");
}

//删除
void main()
{
vector<int> v1(10);
for (int i = 0; i < v1.size(); i++)
{
v1[i] = i + 1;
}

//删除指定位置
vector<int>::iterator it = v1.begin();
it += 3;
v1.erase(it);

//distance(v1.begin(), it);

//删除区间
v1.erase(v1.begin(), v1.begin() + 3);

for (vector<int>::iterator it = v1.begin(); it < v1.end(); it++)
{
if (*it == 5)
{
printf("%x\n", it);
vector<int>::iterator tmp = v1.erase(it); //注意以后开发中编译器版本问题
printf("%x,%x\n",it,tmp);
}
}

//插入
v1.insert(v1.begin() + 2, 100);
v1.insert(v1.end() - 1, 200);

printVector(v1);

system("pause");
}

3.队列deque

//双向队列
#include <deque>
void printDeque(deque<int>& q)
{
for (int i = 0; i < q.size(); i++)
{
cout << q[i] << endl;
}
}

void main()
{
deque<int> d1;
//添加到尾部
d1.push_back(2);
d1.push_back(10);
//添加到头部
d1.push_front(-90);
d1.push_front(-30);

//printDeque(d1);

//cout << d1.front() << endl;
//cout << d1.back() << endl;

//两个方向弹出
//d1.pop_back();
//d1.pop_front();

printDeque(d1);

//查找第一个-90元素索引位置，无需遍历
deque<int>::iterator it = find(d1.begin(),d1.end(),-90);
if (it != d1.end())
{
int idx = distance(d1.begin(), it);
cout << "索引位置为：" << idx << endl;
}

system("pause");
}
//队列（没有迭代器）
/*
void main()
{
queue<int> q;
q.push(78);
q.push(18);
q.push(20);
q.push(33);

//q.front();
//q.back();
while (!q.empty())
{
int tmp = q.front();
cout << tmp << endl;
q.pop();
}
system("pause");
}
*/

//优先级队列
/*
#include <functional>

void main()
{
//默认 最大值优先级
priority_queue<int> pq1;
pq1.push(12);
pq1.push(3);
pq1.push(40);
pq1.push(15);

while (!pq1.empty())
{
int tmp = pq1.top();
cout << tmp << endl;
pq1.pop();
}

cout << "----------" << endl;
//最小值优先级队列
priority_queue<int, vector<int>,greater<int>> pq2;
pq2.push(12);
pq2.push(3);
pq2.push(40);
pq2.push(15);

while (!pq2.empty())
{
int tmp = pq2.top();
cout << tmp << endl;
pq2.pop();
}

system("pause");
}
*/

4.栈stack

//栈
/*
#include <stack>
void main()
{
stack<int> s;
for (int i = 0; i < 10; i++)
{
s.push(i+1);
}

while (!s.empty())
{
int tmp = s.top();
cout << tmp << endl;
s.pop();
}

system("pause");
}
*/

5.集合list,set,map

//list
#include <list>
void printList(list<int>& lst)
{
//迭代器
//没有重载“<”运算符
for (list<int>::iterator it = lst.begin(); it != lst.end(); it++)
{
cout << *it << endl;
}
}
//基本操作
/*
void main()
{
list<int> lst;
for (int i = 0; i < 10; i++)
{
//尾部插入元素
lst.push_back(i);
}

//头部插入元素
lst.push_front(80);
lst.push_front(90);

list<int>::iterator it = lst.begin();
it++;
cout << *it << endl;
//it = it + 3; 注意：不支持随机访问

printList(lst);

system("pause");
}
*/

//删除
/*
void main()
{
list<int> lst;
for (int i = 0; i < 10; i++)
{
//尾部插入元素
lst.push_back(i);
}

list<int>::iterator it = lst.begin();
//删除
it++;
//删除第二个元素
//lst.erase(it);

//删除区间（已经被删除了元素不能再删除）
list<int>::iterator it_begin = lst.begin();
list<int>::iterator it_end = lst.begin();
it_end++;
it_end++;
it_end++;
lst.erase(it_begin, it_end);

//直接根据内容删除元素
lst.remove(5);

printList(lst);

system("pause");
}
*/

//list插入（应用：频繁的修改）
//vector（应用：随机访问v[100]）
/*
void main()
{
list<int> lst;
for (int i = 0; i < 10; i++)
{
//尾部插入元素
lst.push_back(i);
}

list<int>::iterator it = lst.begin();
it++;
lst.insert(it, 100);

printList(lst);
system("pause");
}
*/

//set 元素唯一 默认从小到大
#include <set>

void printSet(set<int> &s)
{
for (set<int>::iterator it = s.begin(); it != s.end(); it++)
{
cout << *it << endl;
}
}
/*
void main()
{
set<int> s;
//添加元素
for (int i = 0; i < 10; i++)
{
s.insert(i+1);
}
s.insert(20);
s.insert(15);
s.insert(15);

//删除
set<int>::iterator it = s.begin();
it++;
s.erase(it);

printSet(s);
system("pause");
}
*/

//元素按照从大到小排列
/*
#include <functional>
void main()
{
//同Java中：Map<String,List<String>>
set<int,greater<int>> s;
s.insert(10);
s.insert(5);
s.insert(20);
s.insert(99);

for (set<int,greater<int>>::iterator it = s.begin(); it != s.end(); it++)
{
cout << *it << endl;
}

system("pause");
}
*/

//元素类型为Teacher对象，按照年龄排序
/*
class Teacher
{
public:
Teacher(char* name, int age)
{
this->name = name;
this->age = age;
}

void print()
{
cout << name << "," << age << endl;
}

public:
char* name;
int age;
};

//自定义排序规则
//仿函数
struct MyAgeSorter
{
bool operator()(const Teacher &left, const Teacher &right)
{
return left.age < right.age;
}
};

void main()
{
set<Teacher, MyAgeSorter> s;
s.insert(Teacher("jack",18));
s.insert(Teacher("rose", 20));
s.insert(Teacher("jason", 22));
s.insert(Teacher("alan", 5));
//s.insert(Teacher("jimy", 5)); //不会插入

for (set<Teacher>::iterator it = s.begin(); it != s.end(); it++)
{
cout << (*it).name << "," << (*it).age << endl;
}

system("pause");
}
*/

//set查找
/*
void main()
{
set<int> s;
//添加元素
for (int i = 0; i < 10; i++)
{
s.insert(i + 1);
}

//printSet(s);

//等于4的元素指针
set<int>::iterator s_4 = s.lower_bound(4);
//cout << *s_4 << endl;
//大于4的元素指针
set<int>::iterator s_5 = s.upper_bound(4);
//cout << *s_5 << endl;

//一次性获取等于4的元素指针，和大于4的元素指针\
//BasicNameValuePair
pair<set<int>::iterator, set<int>::iterator> p = s.equal_range(4);
cout << *p.first << endl;
cout << *p.second << endl;
system("pause");
}
*/

//multiset 允许重复的元素
/*
void main()
{
multiset<int> s;
s.insert(2);
s.insert(8);
s.insert(2);
s.insert(8);

for (multiset<int>::iterator it = s.begin(); it != s.end(); it++)
{
cout <<  *it << endl;
}

system("pause");
}
*/

//map添加元素的方式
#include <map>
#include <string>
/*
void main()
{
//key -> value
//1.
map<int, string> map1;
map1.insert(pair<int, string>(1,"jack"));
map1.insert(pair<int, string>(2, "rose"));

//2
map1.insert(make_pair(3,"jason"));

//3
map1.insert(map<int,string>::value_type(4,"alan"));

//4
map1[5] = "jimmy"; //map["NO1"] = 90;

//前三种方式，如果key已经存在，重复添加会报错
//第四种方式，如果key已经存在，重复添加会覆盖

//遍历输出
for (map<int, string>::iterator it = map1.begin(); it != map1.end(); it++)
{
cout << it->first << "," << it->second << endl;
}

system("pause");
}

*/

void printMap(map<int, string> &map1)
{
for (map<int, string>::iterator it = map1.begin(); it != map1.end(); it++)
{
cout << it->first << "," << it->second << endl;
}
}

//删除
/*
void main()
{
map<int, string> map1;
map1.insert(pair<int, string>(1, "jack"));
map1.insert(pair<int, string>(2, "rose"));
map1.insert(pair<int, string>(3, "jason"));

map<int, string>::iterator it = map1.begin();
it++;
map1.erase(it);

printMap(map1);

system("pause");
}
*/

//添加的结果
/*
void main()
{
map<int, string> map1;
map1.insert(pair<int, string>(1, "jack"));
map1.insert(pair<int, string>(2, "rose"));
map1.insert(pair<int, string>(3, "jason"));
//获取添加的结果（first元素指针，second 是否成功）
pair<map<int, string>::iterator, bool> res = map1.insert(pair<int, string>(3, "alan"));
if (res.second)
{
cout << "添加成功" << endl;
}
else
{
cout << "添加失败" << endl;
}

printMap(map1);

system("pause");
}
*/

//查找
/*
void main()
{
map<int, string> map1;
map1.insert(pair<int, string>(1, "jack"));
map1.insert(pair<int, string>(2, "rose"));
map1.insert(pair<int, string>(3, "jason"));

printMap(map1);

cout << "---------" << endl;

//获取key等于大于5的元素的值
pair<map<int, string>::iterator, map<int, string>::iterator> p = map1.equal_range(2);
if (p.first != map1.end()){
//等于2的元素key value
cout << p.first->first << p.first->second << endl;

//大于2的元素key value
cout << p.second->first << p.second->second << endl;
}

system("pause");
}
*/

//一个key对应多个value
//一个部门多个员工
//multimap
/*
class Employee
{
public:
Employee(char* name,int age)
{
this->name = name;
this->age = age;
}

public:
char* name;
int age;
};

void main()
{
multimap<string, Employee> map1;

//开发部
map1.insert(make_pair("开发", Employee("搁浅", 20)));
map1.insert(make_pair("开发", Employee("彪哥", 20)));

//财务
map1.insert(make_pair("财务", Employee("小颖", 16)));
map1.insert(make_pair("财务", Employee("rose", 20)));

//销售
map1.insert(make_pair("销售", Employee("阿呆", 30)));
map1.insert(make_pair("销售", Employee("呵呵", 30)));

//遍历输出
for (multimap<string, Employee>::iterator it = map1.begin(); it != map1.end(); it++)
{
cout << it->first << "," << it->second.name  << "," << it->second.age << endl;
}

cout << "----------------" << endl;
//只获取“财务”部的员工
//获取“财务部”员工的个数，key对应的value的个数
int num = map1.count("财务");
multimap<string, Employee>::iterator it = map1.find("财务");
int c = 0; //控制循环的次数
while (it != map1.end() && c < num)
{
cout << it->first << "," << it->second.name << "," << it->second.age << endl;
it++;
c++;
}

system("pause");
}
*/
//深拷贝与浅拷贝
/*
class Employee
{
public:
//构造函数
Employee(char* name, int age)
{
this->name = new char[strlen(name) + 1];
strcpy(this->name, name);
this->age = age;
}

//析构函数
~Employee()
{
if (this->name != NULL)
{
delete[] this->name;
this->name = NULL;
this->age = 0;
}
}
//拷贝构造函数
//Employee e =
Employee(const Employee &obj)
{
this->name = new char[strlen(obj.name) + 1];
strcpy(this->name, obj.name);
this->age = obj.age;
}

//重载=
//e1 = e2;
Employee& operator=(const Employee &obj)
{
//释放旧的内存
if (this->name != NULL)
{
delete[] this->name;
this->name = NULL;
this->age = 0;
}

//重新分配
this->name = new char[strlen(obj.name) + 1];
strcpy(this->name, obj.name);
this->age = obj.age;

return *this;
}

public:
char* name;
int age;
};

void func()
{
vector<Employee> v1;
Employee e1("jack",20);
v1.push_back(e1);
}

void main()
{
//vector<Employee> v1;
//Employee e1("jack",20);
//将e1拷贝到vector中
//v1.push_back(e1);

func();

system("pause");
}
*/