for_each是实际开发中最常用的遍历算法，需要熟练掌握

#include#include#includeusing namespace std;//普通函数void myPrint(int val){    cout << val << " ";}//仿函数class myPrint2{public:    void operator()(int val)    {        cout << val << " ";    }};int main(){    vectorv;    for (int i = 0; i < 10; i++)    {        v.push_back(i);    }    for_each(v.begin(), v.end(), myPrint);    cout << endl;    for_each(v.begin(), v.end(), myPrint2());    return 0;}

transform搬运

transform(iterator beg1, iterator end1, iterator beg2, _func);//搬运容器

搬运的目标容器必须提前开辟空间，否则无法正常搬运

(资料图片)

#include#include#includeusing namespace std;class Transform{public:    int operator()(int val)    {        return val;    }};int main(){    vectorv;    for (int i = 0; i < 10; i++)    {        v.push_back(i);    }    vectorv2;    v2.resize(v.size());    transform(v.begin(), v.end(), v2.begin(), Transform());    for (vector::iterator it = v2.begin(); it != v2.end(); it++)    {        cout << *it << " ";    }    return 0;}

常用查找算法

返回一个迭代器，如果没有找到，返回end()

查找自定义数据类型需要重载==运算符，否则底层不知道如何对比

#include#include#includeusing namespace std;//查找内置数据类型void test01(){    vectorv;    for (int i = 0; i < 10; i++)    {        v.push_back(i);    }    //返回一个迭代器，如果没有找到，返回end()    vector::iterator it = find(v.begin(), v.end(), 5);    if (it == v.end())        cout << "没找到" << endl;    else        cout << "找到了" << *it << endl;}//查找自定义数据类型class Person{public:    Person(string name,int age)    {        this->m_age = age;        this->m_name = name;    }    //重载==运算符，让find知道如何对比Person类型数据    bool operator==(const Person& p)    {        if (p.m_age == this->m_age && p.m_name == this->m_name)            return true;        else            return false;    }    string m_name;    int m_age;};void test02(){    //准备数据    Person p1("A", 1);    Person p2("B", 2);    Person p3("C", 3);    Person p4("D", 4);    Person p5("E", 5);    //放入容器中    vectorp;    p.push_back(p1);    p.push_back(p2);    p.push_back(p3);    p.push_back(p4);    p.push_back(p5);    //查找    Person p6("A", 1);    vector::iterator it = find(p.begin(), p.end(), p6);    //输出，验证结果    if (it == p.end())        cout << "没找到" << endl;    else        cout << "找到了" << it->m_name << it->m_age << endl;}int main(){    test01();    test02();    return 0;}

find_if条件查找

find_if(iterator beg, iterator end, _Pred);

#include#include#includeusing namespace std;void test01(){    vectorv;    for (int i = 0; i < 10; i++)    {        v.push_back(i);    }    random_shuffle(v.begin(), v.end());    for (vector::iterator it = v.begin(); it != v.end(); it++)    {        cout << *it << " " ;    }    cout << endl;}int main(){    test01();    return 0;}

#include#include#includeusing namespace std;void Print(int val){    cout << val << " ";}void test01(){    vectorv1;    for (int i = 0; i < 10; i++)    {        v1.push_back(i);    }    vectorv2;    //v2要提前开辟空间    v2.resize(v1.size());    copy(v1.begin(), v1.end(), v2.begin());    for_each(v2.begin(), v2.end(), Print);}int main(){    test01();    return 0;}

#include#include#includeusing namespace std;class Print{public:    void operator()(int val)    {        cout << val << " ";    }};class GreaterFive{public:    bool operator()(const int& val)    {        return val > 5;    }};void test01(){    vectorv1;    vectorv2;    for (int i = 0; i < 10; i++)    {        v1.push_back(i);        v2.push_back(i + 2);    }    //交换前    for_each(v1.begin(), v1.end(), Print());    for_each(v2.begin(), v2.end(), Print());    cout << endl;    //交换后    swap(v1, v2);    for_each(v1.begin(), v1.end(), Print());    for_each(v2.begin(), v2.end(), Print());}int main(){    test01();    return 0;}

#include#include#include#includeusing namespace std;void myPrint(int val){    cout << val << " ";}void test01(){    vectorv1;    vectorv2;    for (int i = 0; i < 10; i++)    {        v1.push_back(i);        v2.push_back(i + 2);    }    for_each(v1.begin(), v1.end(), myPrint);    cout << endl;    for_each(v2.begin(), v2.end(), myPrint);    cout << endl;    //目标容器需要提前开辟空间，最特殊的情况，大容器包含小容器    vectorv3;    v3.resize(min(v1.size(), v2.size()));    //取交集    vector::iterator itEnd = set_intersection(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin());    for_each(v3.begin(), itEnd, myPrint);    cout << endl;    //如果不用返回的itEnd，会把0也给打印出来    for_each(v3.begin(), v3.end(), myPrint);}int main(){    test01();    return 0;}