C++函数对象Functor与匿名函数对象Lambda表达式详解

#include <iostream>
using namespace std;
template <class T1>
class A
{
    T1 name;
public:
    A(T1 name)
    {
        this->name=name;
    }
    void operator()()
    {
        cout<<this->name<<endl;
    }
};
int main()
{
    A<string> a("da jia hao");
    a();
    return 0;
}

#include <iostream>
using namespace std;
template <class T>
T my_bigger(T a,T b)
{
    return a>b?a:b;
}
template <class T>
T my_less(T a,T b)
{
    return a>b?b:a;
}
template <class T,class Compare>
T my_compare(T a, T b,Compare f)
{
    return f(a,b);
}
int main()
{
    cout<< my_compare<int>(10,20,my_less<int>)<<endl;
    cout<<my_compare<int>(10,20,my_bigger<int>)<<endl;
    return 0;
}

#include <iostream>
using namespace std;
template <class T,class Compare>
T my_compare(T a, T b,Compare f)
{
    return f(a,b);
}
template <class T>
class A
{
public:
    T operator()(T a,T b)
    {
        return a>b?a:b;
    }
};
template <class T>
class B
{
public:
    T operator()(T a,T b)
    {
        return a>b?b:a;
    }
};
int main()
{
    cout<<my_compare(10,20,A<int>())<<endl;
    cout<<my_compare(10,20,B<int>())<<endl;
    return 0;
}

#include <iostream>
using namespace std;
class A
{
public:
    A()
    {
    }
    void operator()()
    {
    }
};
int main()
{
    auto f=[]()->void{cout<<"我是大哥"<<endl;};
    f();
    return 0;
}

#include <iostream>
using namespace std;
class A
{
    int a;
public:
    A(int &a)
    {
        this->a=a;
    }
    void operator()()
    {
    }
};
int main()
{
    int a=10;
    int b=20;
    auto f=[&]()->void
    {
        int temp=a;
        a=b;
        b=temp;
    };
    f();
    cout<<a<<endl;
    cout<<b<<endl;
    return 0;
}

#include <iostream>
using namespace std;
class A
{
    int a;
public:
    A(int &a)
    {
        this->a=a;
    }
    void operator()()
    {
    }
};
int main()
{
    int a=10;
    int b=20;
    auto f=[=]()mutable
    {
        int temp=a;
        a=b;
        b=temp;
    };
    f();
    return 0;
}