c 链表实例

#include <stdio.h>
#include <stdlib.h> 

struct node
{ 
	int data;  
	struct node *next;
};
typedef struct node NODE;
typedef struct node * PNODE;
PNODE constructlist( PNODE head, int num );   
void outlist( PNODE head );   
void deleteneg( PNODE head );   


int main(int argc, char *argv[])
{
	printf("Hello, world\n");
	int num=1;         
	PNODE head;              
	head = (PNODE)malloc( sizeof(NODE) ); 
	head->next = NULL;         
	head->data = -1; 

	while ( num!=0 )
	{
		scanf("%d", &num);
		if ( num!=0 )                
			constructlist (head, num);          
	}
	deleteneg( head );       
	outlist( head );
	return 0;
}

PNODE constructlist( PNODE head, int num )
{
	PNODE p;       
	p = (PNODE)malloc( sizeof(NODE) ); 

	p->data = num;       
	p->next = head->next;        
	head->next = p;       
	return head;
}

void outlist( PNODE head )     
{   
	PNODE p;         
	p = head->next;         
	while ( p != NULL )         
	{   
		printf("%d\n", p->data);             
		p = p->next;         
	}     
}
//删除所有无效数值结点的函数原型：
void deleteneg(PNODE head)
{
    PNODE p,prev;         
    p = head->next; 
	prev = NULL;

    while ( p != NULL )         
    {   
        if( p->data < 0)
        {
            if(prev == NULL)
			{
				head->next = p->next;
				free(p);
				p = head->next;
			}
			else 
			{
				prev->next = p->next;
				free(p);
				p = prev;
				p = p->next;
			}
        }
        else 
		{
			prev = p;
			p = p->next;
		}    
    } 
}