Question

求解C加加

定义一个DOG类，它用静态数据成员DOGS记录了DOG的数目，静态成员函数CATDOGS用来存取DOGS.设计并测试这个类

Answer 1

#include<iostream.h>
//DOG类
class DOG;
class DOG
{
public:
DOG()
{
++DOGS;
}
virtual~DOG()
{
--DOGS;
}
public:
static unsigned int GetDOGS()
{
return DOGS;
}
private:
static unsigned int DOGS;
};

unsigned int DOG:: DOGS=0;
//测试
void main()
{
cout<<DOG::GetDOGS()<<endl;
DOG* p[5]={
new DOG(),
new DOG(),
new DOG(),
new DOG(),
new DOG()
};

cout<<DOG::GetDOGS()<<endl;
delete p[4];
delete p[3];
cout<<DOG::GetDOGS()<<endl;

p[3]=new DOG(); cout<<DOG::GetDOGS()<<endl;
for(int i=0;i<4;i++) delete p[i];
cout<<DOG::GetDOGS()<<endl;
}