自定义类型都要用仿函数判断

 1.find()

class Person
{
public:Person(string name,int age){this->m_Name = name;this->m_Age = age;}bool operator==(const Person &p)//重载operator={if (this->m_Name == p.m_Name && this->m_Age == p.m_Age){return true;}return false;}string m_Name;int m_Age;
};
void test01()//find查找内置类型
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(30);v1.push_back(40);v1.push_back(50);//find查找内置类型auto it = find(v1.begin(), v1.end(), 40);//auto自动推出it类型(vector<int>::iterator)if (it == v1.end()){cout << "没找到这个元素" << endl;}else{cout << "找到这个元素：" << *it << endl;}
}
void test02()find查找自定义类型//类内部要重载operator=
{vector<Person> p;Person p1("张三", 10);Person p2("李四", 15);Person p3("王五", 13);Person p4("赵六", 16);p.push_back(p1);p.push_back(p2);p.push_back(p3);p.push_back(p4);Person pf("赵六", 14);auto it = find(p.begin(), p.end(), pf);//auto自动推出it类型(vector<int>::iterator)if (it == p.end()){cout << "没找到这个人" << endl;}else{cout << "找到了，姓名：" << it->m_Name << " 年龄：" << it->m_Age << endl;}
}

2.find_if()

class Person
{
public:Person(string name,int age){this->m_Name = name;this->m_Age = age;}string m_Name;int m_Age;
};
class Greater20//test01
{
public:bool operator()(int val){return val > 20;}};
class MyCompare//test02
{
public:bool operator()(Person& p){return (p.m_Age > 15);}
};
void test01()//find_if查找内置类型
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(30);v1.push_back(40);v1.push_back(50);vector<int>::iterator it=find_if(v1.begin(), v1.end(), Greater20());cout << "找到了：" << *it << endl;
}
void test02()find_if查找自定义类型
{vector<Person> p;Person p1("张三", 10);Person p2("李四", 15);Person p3("王五", 13);Person p4("赵六", 16);p.push_back(p1);p.push_back(p2);p.push_back(p3);p.push_back(p4);Person pf("赵六", 16);vector<Person>::iterator it = find_if(p.begin(), p.end(),MyCompare());if (it == p.end()){cout << "没找到这个人" << endl;}else{cout << "找到了，姓名：" << it->m_Name << " 年龄：" << it->m_Age << endl;}
}

3.adjacent_find()

void test01()
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(40);v1.push_back(30);v1.push_back(40);v1.push_back(40);v1.push_back(50);vector<int>::iterator it = adjacent_find(v1.begin(), v1.end());//查找相邻相同元素cout << "找到了：" << *it << endl;
}

4.binary_search()//二分查找

void test01()
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(40);v1.push_back(30);v1.push_back(40);v1.push_back(40);v1.push_back(50);sort(v1.begin(), v1.end());//降序不行bool ret = binary_search(v1.begin(), v1.end(), 30);if (ret){cout << "找到了" << endl;}else{cout << "没找到" << endl;}
}

5.count()

class Person
{
public:Person(string name,int age){this->m_Name = name;this->m_Age = age;}bool operator==(const Person& p){if (this->m_Age == p.m_Age)//按年龄查找年龄相等的人的个数{return true;}return false;}string m_Name;int m_Age;
};
void test01()//count查找内置类型
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(40);v1.push_back(30);v1.push_back(40);v1.push_back(40);v1.push_back(50);int num = count(v1.begin(), v1.end(), 40);//统计40的个数cout << "40的个数是：" << num << endl;}
void test02()//count查找自定义类型
{vector<Person> p;Person p1("张三", 10);Person p2("李四", 15);Person p3("王五", 15);Person p4("赵六", 16);p.push_back(p1);p.push_back(p2);p.push_back(p3);p.push_back(p4);Person pf("张麻子", 15);int num = count(p.begin(), p.end(), pf);cout << "num=" << num << endl;
}

6.count_if()

class Person
{
public:Person(string name,int age){this->m_Name = name;this->m_Age = age;}string m_Name;int m_Age;
};
class MyCompare
{
public:bool operator()(const int val){return val > 30;}
};
class AgeGreater14
{
public:bool operator()(const Person& p){return p.m_Age > 14;//统计年龄大于14的人的个数}
};
void test01()//count_if统计内置类型
{vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(40);v1.push_back(30);v1.push_back(40);v1.push_back(40);v1.push_back(50);int num = count_if(v1.begin(), v1.end(), MyCompare());//统计大于30的个数cout << "大于30的个数是：" << num << endl;}
void test02()//count_if统计自定义类型
{vector<Person> p;Person p1("张三", 10);Person p2("李四", 14);Person p3("王五", 15);Person p4("赵六", 16);p.push_back(p1);p.push_back(p2);p.push_back(p3);p.push_back(p4);int num = count_if(p.begin(), p.end(),AgeGreater15());cout << "num=" << num << endl;
}