为什么输出的结果是错误的

Question

#include <iostream>using namespace std;int month;//全局变量  int day;  int year;void Set(int m,int d,int y)// -----------------------------------------------------a{       ::month=m; //-----------------------------------------------------①       ::day=d;        ::year=y;}class CDate{public:        void Set(int m,int d,int y)// -----------------------------------------------------b        {              ::Set(m,d,y); //-----------------------------------------------------②       }       void Print()       {               cout<<month<<"/"<<day<<"/"<<year<<endl;       }private:        int month; //成员变量       int day;        int year;}; void main(){       CDate  a;    a.Set(10,15,2007) ;       a.Print();}

Answer 1

print方法里输出的是类的私有成员变量 而set方法里修改的是全局变量