帮我看看这个循环单链表为什么总是输出的时候只有一个元素

[geyao1266]

#include<iostream.h>
struct conf
{
int data;
conf *next;
};

class circle
{
private:
conf *first;
conf *last;
public:
void init(circle & b1)
{
b1.first = new conf;
conf *p;
p = b1.first;
int n;
cout<<"请输入元素个数:";
cin>>n;
cout<<endl;
for(int i = 0;i<n;i++)
{

conf *q;
q = new conf;
cout<<"第"<<i+1<<"个数据为:";
cin>>q->data;
cout<<endl;
p->next=q;

}
b1.last = p;
b1.last->next = b1.first->next;


}

void del(circle &b1)
{
conf *p;
p=b1.first;
b1.first->next = b1.first->next->next;
b1.last->next = p->next->next;
p->next = NULL;
}

int length(circle &b1)
{
conf *p=b1.first->next;
int count = 0;
while(p->next= b1.)
{
p=p->next;
count++;
}
return (count+1);
}

void disp(circle& b1)
{
conf *p;
cout<<"循环链表中数据为:"<<endl;
p = b1.first;
if(p !=b1.last)
{
cout<<p->next->data<<" ";
p = p->next;
}
cout<<endl;
}
};

void main()
{
circle b1;
b1.init(b1);
b1.disp(b1);

int a =b1.length(b1);
cout<<"循环链表的元素个数为:"<<a<<endl;

/*b1.del(b1);
b1.disp(b1);
a = b1.length(b1);
cout<<"循环链表的元素个数为:"<<a<<endl;*/


}

[ryfdizuo]

void disp(circle& b1) 
{ 
conf *p; 
cout < <"循环链表中数据为:" < <endl; 
p = b1.first; 
    if(p !=b1.last)   //这里最起码应该是循环了吧？
{ 
cout < <p-> next-> data < <"  "; 
p = p-> next; 
} 
cout < <endl; 
} 
}; 

[geyao1266]

我是这么想的在这地方用一个循环输出，但是结果并不对
我觉得应该是初始化的问题

[ryfdizuo]

struct conf 
{ 
	int data; 
	conf *next; 
	conf():next(NULL)
	{}
}; 
你可以这样子：next初始化为NULL

[lzy340623339]

其实既然你已经有了链头指针和链尾指针,干吗还要是循环链表呢?

[Chappell]

void init(circle & b1)
有问题

[geyao1266]

还是一样，无法输出
我觉得问题应该是初始化时头指针和尾指针的问题，但又不知道怎么改

[geyao1266]

你的意思是我应该把尾指针给去掉是么
我这样做感觉处理起来会方便一点

[lzy340623339]

刚才说错了点,是有了循环,就不必要用尾指针了
这个是正确运行的程序

#include  <iostream> 
using namespace std; 


struct conf 
{ 
int data; 
conf *next; 
}; 

class circle 
{ 
private: 
conf *first; 
        conf *last; 
public: 
    void init(circle & b1) 
{ 
    b1.first = new conf; 
conf *p; 
                p = b1.first; 
int n; 
cout<<"请输入元素个数:"; 
cin>> n; 
cout<<endl; 
for(int i = 0;i <n;i++) 
{ 

conf *q; 
q = new conf; 
cout<<"第"<<i+1<<"个数据为:"; 
cin>> q-> data; 
cout<<endl; 
q->next=NULL;
p-> next=q; 
p=q;

} 
    b1.last = p; 
    b1.last-> next = b1.first-> next; 


} 

void del(circle &b1) 
{ 
conf *p; 
p=b1.first; 
b1.first-> next = b1.first-> next-> next; 
        b1.last-> next = p-> next-> next; 
p-> next = NULL; 
} 

int length(circle &b1) 
{ 
conf *p=b1.first-> next; 
int count = 0; 
while(p-> next= b1.first->next) 
{ 
p=p-> next; 
count++; 
} 
return (count+1); 
} 

void disp(circle& b1) 
{ 
conf *p; 
cout<<"循环链表中数据为:"<<endl; 
p = b1.first->next; 
if(p!=0)
do  
{ 
cout<<p->data<<"  "; 
p = p-> next; 
}while(p !=b1.first->next);
cout<<endl; 
} 
}; 

void main() 
{ 
circle b1; 
b1.init(b1); 
    b1.disp(b1); 

int a =b1.length(b1); 
cout<<"循环链表的元素个数为:"<<a<<endl; 

/*b1.del(b1); 
b1.disp(b1); 
a = b1.length(b1); 
cout<<"循环链表的元素个数为:"<<a<<endl;*/ 


}

[geyao1266]

我知道是这个函数的里面的错误，但不知道应该怎么改
我现在把尾指针去掉试试

[geyao1266]

恩，问题解决了。能不能再详细解释一下改动的代码的意义。谢谢

[geyao1266]

问题全部解决...谢谢大家~

[Lynn_Ran]

希望对lz有帮助 ^_^

#include <iostream> 
using namespace std;

struct conf 
{ 
	int data; 
	conf *next; 
}; 

class circle 
{ 
private: 
	conf *first; 
	conf *last; 
public: 
	void init(circle &b1);  //创建
	void del(circle &b1);  //删除
	int length(circle &b1);  //求长
	void disp(circle &b1);  //打印
}; 

void circle::init(circle &b1)
{ 
	b1.first = new conf; 
	conf *p; 
	p = b1.first; 
	int n; 
	cout << "请输入元素个数:"; 
	cin >> n; 
	cout << endl; 
	for( int i=0; i<n; i++ ) //<====这个循环有问题，不能形成链表
	{ 
		conf *q = new conf;
		cout << "第" << i+1 <<"个数据为:"; 
		cin >> q->data; 
		cout << endl; 
		q->next = NULL;
		p->next = q; 
		p = q;
	} 
	b1.last = p; 
	b1.last->next = b1.first->next; 
} 

void circle::del(circle &b1) //我做的是删除第一个结点，别的大同小异
{ 
	conf *p; 
	p = b1.first->next;
	b1.first->next = b1.first->next->next; 
	p->next = NULL; 
} 

int circle::length(circle &b1) 
{ 
	conf *p = b1.first->next; 
	int count = 0; 
	while( p != b1.last)//<===== 
	{ 
		p = p->next; 
		count++; 
	} 
	return (count+1); 
} 

void circle::disp(circle &b1) 
{ 
	conf *p; 
	cout << "循环链表中数据为:" ; 
	if ( p = b1.first->next )//<====
	{
		while ( p != b1.last ) 
		{ 
			cout << p->data << "  "; 
			p = p->next; 
		} 
		cout << p->data << endl;
	}
	else
		cout << "此链表为空" << endl;
	return;
} 

void main() 
{ 
	circle b1; 
	b1.init(b1); 
    b1.disp(b1); 
	int a =b1.length(b1); 
	
	cout << "循环链表的元素个数为:" << a << endl; 

	b1.del(b1); 
	b1.disp(b1); 
	a = b1.length(b1); 
	cout << "循环链表的元素个数为:" << a << endl;

	system("pause");
	return;
}

[geyao1266]

恩，肯定有用，谢谢~