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 
#include 
#include  //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 
void printVector(vector &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 v1;
    v1.push_back(20);
    v1.push_back(40);
    v1.push_back(15);
    v1.push_back(7);

    //2.
    vector v2 = v1;

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

    printVector(v3);


    system("pause");
}

//添加 删除
void main()
{
    //添加到结尾
    vector 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 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 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 v1;
    v1.push_back(20);
    v1.push_back(40);
    v1.push_back(15);
    v1.push_back(7);
    //正向
    for (vector::iterator it = v1.begin(); it < v1.end(); it++)
    {
        cout << *it << endl;
    }
    cout << "-----------------" << endl;
    //反向迭代
    for (vector::reverse_iterator it = v1.rbegin(); it < v1.rend(); it++)
    {
        cout << *it << endl;
    }

    system("pause");
}

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

    //删除指定位置
    vector::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::iterator it = v1.begin(); it < v1.end(); it++)
    {
        if (*it == 5)
        {       
            printf("%x\n", it);
            vector::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 
void printDeque(deque& q)
{
    for (int i = 0; i < q.size(); i++)
    {
        cout << q[i] << endl;
    }
}

void main()
{
    deque 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::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 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 

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

    list::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::iterator it_begin = lst.begin();
    list::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 lst;
    for (int i = 0; i < 10; i++)
    {
        //尾部插入元素
        lst.push_back(i);
    }

    list::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 

void printSet(set &s)
{
    for (set::iterator it = s.begin(); it != s.end(); it++)
    {
        cout << *it << endl;
    }
}
/*
void main()
{
    set 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::iterator it = s.begin();
    it++;
    s.erase(it);    

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

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

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

    system("pause");
}
*/

//set查找
/*
void main()
{
    set 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::iterator s_4 = s.lower_bound(4); 
    //cout << *s_4 << endl;
    //大于4的元素指针
    set::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::iterator, set::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 s;
    s.insert(2);
    s.insert(8);
    s.insert(2);
    s.insert(8);

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

    system("pause");
}
*/


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

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

    //3
    map1.insert(map::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::iterator it = map1.begin(); it != map1.end(); it++)
    {
        cout << it->first << "," << it->second << endl;     
    }


    system("pause");
}

*/

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

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

    map::iterator it = map1.begin();
    it++;
    map1.erase(it);

    printMap(map1);

    system("pause");
}
*/

//添加的结果
/*
void main()
{
    map map1;
    map1.insert(pair(1, "jack"));
    map1.insert(pair(2, "rose"));
    map1.insert(pair(3, "jason"));
    //获取添加的结果（first元素指针，second 是否成功）
    pair::iterator, bool> res = map1.insert(pair(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 map1;
    map1.insert(pair(1, "jack"));
    map1.insert(pair(2, "rose"));
    map1.insert(pair(3, "jason")); 

    printMap(map1);

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

    //获取key等于大于5的元素的值
    pair::iterator, map::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 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::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::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 v1;
    Employee e1("jack",20); 
    v1.push_back(e1);
}

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

    func();

    system("pause");
}
*/