C++学习笔记(字符串string、vector_deque、queue,multiset、map、multimap、容器拷贝问题)

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)

2016-09-12 11:04 77人阅读评论(0) 收藏 举报

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【c/c++开发】（7）

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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");

}

*/