//myApplication.cpp
#include "myapplication.h"
#include <iostream>
using std::cout;
using std::endl;
myApplication::myApplication(string _appName):appName(_appName)
{
if(self!=0)
return;
else
self=this;
}
void myApplication::printAppname()
{
cout<<appName<<endl;
}
myApplication* myApplication::self=0;//myApplication.h
#ifndef MYAPPLICATION_H_INCLUDED
#define MYAPPLICATION_H_INCLUDED
#include <string>
using std::string;
#define myApp myApplication::instance()
class myApplication
{
public:
myApplication(string _appname);
static myApplication* instance() {return self;}
void printAppname();
private:
static myApplication *self;
string appName;
};
#endif // MYAPPLICATION_H_INCLUDED 看到了myApplication* myApplication::self=0;这一行我就有点犯糊涂了。为什么要这样赋值呢？可不可以在类里面赋值呢？我试了试，答案是不可以的。查了一下C++规定了类的静态成员变量要在类外赋值。我有了疑问，为什么要这样规定呢？原文地址：http://blog.csdn.net/cqu20093154/article/details/42707883
