为什么不能返回对象的指针？？

[rhs]

#include<iostream>
#include<stdlib.h>
class base
{
public:
base( ){cout<<"I have been successful!!\n";}
};
class extend
{
public:
extend( ){mybase=NULL;}
base *GetDC( ){return mybase;}
private:
base *mybase;
};
int main( )
{
extend *app=new extend( );
app->GetDC( )=new base();//这儿有问题
system("pause");
return 0;
}
用dev-c++编译时：non-lvalue in assignment，说没有左值。为什么呢？

[ttlb]

up

[Wolf0403]

base *GetDC( ){return mybase;} 改成返回引用
base *& GetDC() {return mybase;} 就可以了。引用是 lvalue