奇怪的错误

[piaomiao163]

#include <iostream>
using namespace std;

struct treeNod;

struct headTreeNod
{
int length;
treeNod *next;
};

struct treeNod
{
treeNod *lchild, *rchild;
};

class tree
{
public:
tree();
void creatTree( treeNod *pTmp );
private:
headTreeNod *pheadNod;
};

tree::tree()
{
pheadNod->length = 0;
//pheadNod->next = NULL;
}

void tree::creatTree( treeNod *pTmp )
{
int i;
cout << "请输入结点标识符" << endl;
cin >> i;
if( i == 0 )
pTmp = NULL;
else
{
if( pheadNod->next == NULL )
{
pheadNod->next = pTmp;
}

this->creatTree( pTmp->lchild );
this->creatTree( pTmp->rchild );
}
}

int main()
{
tree tree1;
treeNod *pTmp;

//tree1.creatTree( pTmp );
return 0;
}




在初始化一个对象的时候 pheadNod->length = 0; 这一步出错了·~~~


···郁闷·~帮忙看看为什么？？语法没错误！！

[liao05050075]

#include <iostream> 
using namespace std; 

struct treeNod; 

struct headTreeNod 
{ 
    int length; 
	treeNod *next; 
}; 

struct treeNod 
{ 
    treeNod *lchild, *rchild; 
}; 

class tree 
{ 
public: 
	tree(); 
	void creatTree( treeNod *pTmp ); 
private: 
	headTreeNod *pheadNod; 
}; 

tree::tree() 
{ 
	//你还没有为pheadNod申请空间就要去改它的内容，当然会错啦，加个new就行了
	pheadNod=new headTreeNod;
    pheadNod->length = 0; 
	//pheadNod->next = NULL; 
} 

void tree::creatTree( treeNod *pTmp ) 
{ 
	int i; 
	cout << "请输入结点标识符" << endl; 
	cin >> i; 
    if( i == 0 ) 
		pTmp = NULL; 
	else 
	{ 
		if( pheadNod->next == NULL ) 
		{ 
			pheadNod->next = pTmp; 
		} 
		
		this->creatTree( pTmp->lchild ); 
		this->creatTree( pTmp->rchild ); 
	} 
} 

int main() 
{ 
    tree tree1; 
	treeNod *pTmp; 
	
	//tree1.creatTree( pTmp ); 
	return 0; 
} 

[光宇广贞]

private:
headTreeNod *pheadNod;
};

tree::tree()
{
pheadNod->length = 0;
//pheadNod->next = NULL;
}

有错，只可能你这个 pheadNod 没有给丫申请空间，丫是一个野指针。

[pengzhixi]

tree::tree()
{
pheadNod->length = 0; //你这个pheadNod都没分配内存,你就使用其中的数据
//pheadNod->next = NULL;
}

[piaomiao163]

失误失误！！！！！！！！！！！惭愧！！！！！！！！！

[adventurelw]

tree::tree()
{
pheadNod->length = 0;
//pheadNod->next = NULL;
}

pheadNod并没有明确指向，当然不能初始化啊。。。。。。通常，这种情况都需要动态分配的。

[pengzhixi]

逻辑很乱.struct headTreeNod
{
int length;
treeNod *next;
};

struct treeNod
{
treeNod *lchild, *rchild;
};为什么不合成一个类呢?