请问包含结构指针的结构体怎么初始化?

[snoopy84]

struct Base
{
int a;
int b;
int c;
};

struct Derived
{
int d;
int e;
int f;
base *pb;
};

derived *CreateDerived (void){}
void FreeDerived (derived *pd){}
要求完成这两个函数,并可以使用如下的语句,
Derived *p = CreateDerived();
p->pb->a = 10;

[snoopy84]

谢谢各位大侠,我结贴了

[唐巧]

在C++中,struct被当成class来编译的,所以也可以写成下面这样,增加构造函数和析构函数:

#include  <iostream> 
using namespace std; 
struct Base 
{ 
    int a; 
    int b; 
    int c; 
}; 

struct Derived 
{ 
    int d; 
    int e; 
    int f; 
    Base *pb; 
    Derived(){
       pb = new Base;
    }
    ~Derived(){
       delete pb; 
    }
}; 

int main(int argc, char* argv[]) 
{
    Derived *p = new Derived();
    p->pb->a = 10;
    delete p;
    return 0; 
} 

[snoopy84]

不好意思,各位大侠都应当给分的,下次下次,请别见怪,第一次问问题,呵呵

[snoopy84]

要求用malloc

[珍惜生命远离CPP]

Derived * CreateDerived()
{
  Derived *p = new Derived;
  p->pb = new Base;
  return p;
}

void FreeDerived(Derived *p)
{
  delete p->pb;
  delete p;
}

[Supper_Jerry]

#include  <iostream> 
using namespace std; 
struct Base 
{ 
	int a; 
	int b; 
	int c; 
}; 

struct Derived 
{ 
	int d; 
	int e; 
	int f; 
	Base *pb; 
}; 
Derived *CreateDerived (void)
{
	Derived* pD = new Derived;
	if(pD)
	{
		pD->pb = new Base;
		return pD;
	}
	return NULL;
} 
void FreeDerived (Derived *pd)
{
	if(pd)
	{
		if(pd->pb)
		{
			delete pd->pb;
			pd->pb = NULL;
		}
		delete pd;
		pd = NULL;
	}
}

int main(int argc, char* argv[]) 
{
	Derived *p = CreateDerived(); 
	p->pb->a = 10;
	FreeDerived(p);
	return 0; 
} 

[珍惜生命远离CPP]

Derived * CreateDerived()
{
  Derived *p = (Derived *)malloc( sizeof(Derived) );
  p->pb = (Base*)malloc(sizeof(Base));
  return p;
}

void FreeDerived(Derived *p)
{
  free( p->pb);
  free(p);
}

[Supper_Jerry]

#include  <iostream> 
using namespace std; 
struct Base 
{ 
	int a; 
	int b; 
	int c; 
}; 

struct Derived 
{ 
	int d; 
	int e; 
	int f; 
	Base *pb; 
}; 
Derived *CreateDerived (void)
{
	Derived* pD = (Derived*)malloc(sizeof(Derived));
	if(pD)
	{
		pD->pb = (Base*)malloc(sizeof(Base));
		return pD;
	}
	return NULL;
} 
void FreeDerived (Derived *pd)
{
	if(pd)
	{
		if(pd->pb)
		{
			free(pd->pb);
			pd->pb = NULL;
		}
		free(pd);
		pd = NULL;
	}
}

int main(int argc, char* argv[]) 
{
	Derived *p = CreateDerived(); 
	p->pb->a = 10;
	FreeDerived(p);
	return 0; 
} 

使用malloc free

[太乙]

Derived *CreateDerived (void)
{
   return malloc(sizeof(struct Derived));

} 
void FreeDerived (Derived *pd)
{
   if(pd==null)return;
   if(pd->pb!=null)free(pd->pb);
   free(pd);
} 

[ryfdizuo]

[Quote=引用 4 楼 akirya 的回复:]
C/C++ code


Derived * CreateDerived()
{
Derived *p = (Derived *)malloc( sizeof(Derived) );
p->pb = (Base*)malloc(sizeof(Base));
return p;
}

void FreeDerived(Derived *p)
{
free( p->pb);
free(p);
}
[/Quote]

[laolaoliu2002]

5楼写的很标准