C++，关于类和结构体中，成员访问属性(public,private)

#include <vector> 
#include <iostream> 
#include <algorithm>
#include <functional>
struct State 
{ 
    State( int state ) : m_state( state ){} 
    ~State() { std::cout << "~State(), m_state=" << m_state << std::endl; } 
    void setState( int state ){ m_state = state; } 
    int getState() const{ return m_state; } 
    void print() const { std::cout << "State::print: " << m_state << std::endl; } 
private: 
    int m_state; 
}; 
//void Print(State *pstate) //全局函数
//{
//    pstate->print();
//}

class Printer //改用仿函数
{
    void operator()(State *pstate)
    {
        pstate->print();
    }
};

/*
class Printer //仿函数，用模板实现
{
    template<typename T> void operator()(T *pstate)
    {
        pstate->print();
    }
};
*/
int main() 
{ 
    std::vector<State*> vect; 
    vect.push_back( new State(0) ); 
    vect.push_back( new State(1) ); 
    vect.push_back( new State(2) ); 
    vect.push_back( new State(3) ); 
    std::vector<State*>::iterator it( vect.begin() ); 
    std::vector<State*>::iterator ite( vect.end() ); 
//    for ( ; it != ite; ++it ) 
//    { 
//        (*it)->print(); 
//    } 
//    std::for_each(it,ite,&Print); //调用函数指针
    std::for_each(it,ite,Printer()); //调用仿函数
    system( "pause" ); 
    return 0; 
}

class Printer //改用仿函数
{
public:         //不能省略，不写public，默认为private
    void operator()(State *pstate)
    {
        pstate->print();
    }
};