数据结构：交换单链表中的任意两元素--C实现

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

struct node
{
int data ;
node * next;
};
//前驱节点
node* FindPre( node* head , node* p )
{
node *q = head
while( q )
{
if( q->next == p )
{
return p;
}
else
{
q = q -> next;
}
}
return NULL;
}
//节点交换
bool SwapNode( node* head , node* p , node* q )
{
bool flag = false;
if( head == NULL || p == NULL || q == NULL )
{
printf("invalid parameter: NULL\n");
}
if( p->data == q->data )
{
flag = true;
}
if( p->next == q )
{
node* pre = FindPre( head , p );
pre->next = q;
p->next = q->next;
q->next = p;
flag = true;
}
else if( q->next = p )
{
node* pre = FindPre( head , q );
pre->next = p;
q->next = p->next;
p->next = q;
flag = true;
}
else
{
node* pre_p = FindPre( head , p );
node* pre_q = FindPre( head , q );
node* aft_p = p->next;
p->next = q->next;
q->next = aft_p;
pre_p->next = q;
pre_q->next = p;
falg = true;
}
return flag;
}