函数对象适配器

class MyPrint : public binary_function<int, int, void>{
public:
    void operator()(int v, int val) const{
        cout << "v: " << v << ", val: " << val << ", v + val: " << v + val << endl;
    }
};
void myPrint(int v, int val){
    cout << v + val << " ";
}
class MySort: public binary_function<int, int, bool>{
public:
    bool operator() (int lhs, int rhs)const{
        return lhs > rhs;
    }
};
class MyGreater: public unary_function<int, bool>{
public:
    bool operator()(int v)const{
        return v > 50;
    }
};

void printVec(const vector<int> &v){
    for(const auto &p : v){
        cout << p << " ";
    }
    cout << endl;
}
class Person{
public:
    Person(int id, int age):id(id), age(age){}
    void show(){
        cout << "id: " << id << ", age: " << age << endl;
    }
    int id;
    int age;
};
int main(){

    vector<int> v;
    for(int i = 0; i < 10; ++i){
        v.push_back(rand() % 100);
    }
    // bind1st bind2nd
    for_each(v.begin(), v.end(), bind1st(MyPrint(), 100));
    cout << endl;
    // ptr_fun
    for_each(v.begin(), v.end(), bind2nd(ptr_fun(myPrint), 100)); 
    cout << endl;
    printVec(v);
    // not1 not2
    sort(v.begin(), v.end(), not2(MySort()));
    printVec(v);
    auto it = find_if(v.begin(), v.end(), not1(MyGreater()));
    if(it != v.end()){
        cout << *it << endl;
    }
    // mem_fun_ref mem_fun
    vector<Person> vp;
    vp.emplace_back(Person(1, 2));
    vp.emplace_back(Person(3, 4));
    vp.emplace_back(Person(5, 6));
    for_each(vp.begin(), vp.end(), mem_fun_ref(&Person::show));
    cout << "--------------" << endl;
    vector<Person*> vpp;
    vpp.emplace_back(new Person(1, 2));
    vpp.emplace_back(new Person(3, 4));
    vpp.emplace_back(new Person(5, 6));
    for_each(vpp.begin(), vpp.end(), mem_fun(&Person::show));
    return 0;
}

v: 100, val: 83, v + val: 183
v: 100, val: 86, v + val: 186
v: 100, val: 77, v + val: 177
v: 100, val: 15, v + val: 115
v: 100, val: 93, v + val: 193
v: 100, val: 35, v + val: 135
v: 100, val: 86, v + val: 186
v: 100, val: 92, v + val: 192
v: 100, val: 49, v + val: 149
v: 100, val: 21, v + val: 121

183 186 177 115 193 135 186 192 149 121 
83 86 77 15 93 35 86 92 49 21 
15 21 35 49 77 83 86 86 92 93 
15
id: 1, age: 2
id: 3, age: 4
id: 5, age: 6
--------------
id: 1, age: 2
id: 3, age: 4
id: 5, age: 6