C语言：非减链表的合并

/*
a,b是两个非减单链表，把它们合并成一个新的链表，元素也是非减的
*/
# include <stdio.h>
# include <malloc.h>

typedef struct node
{
int data;
struct node * pNext;

}NODE, *PNODE;

PNODE creat_list();  //创建链表
void travese(PNODE pHead);  //遍历链表
PNODE union_list(PNODE pA, PNODE pB);  //有顺序的合并两个链表

int main(void)
{
//创建链表A
PNODE pA = creat_list();
travese(pA);

//创建链表B
PNODE pB = creat_list();
travese(pB);

//生成合并链表C
PNODE pC = union_list(pA, pB);
travese(pC);

return 0;
}

//创建链表
PNODE creat_list()
{
int i, val;
int len;

PNODE pHead = (PNODE)malloc(sizeof(NODE));  //创建头结点
pHead->pNext = NULL;

PNODE pNew;
PNODE pTail = pHead;  //指向尾节点

printf("链表的长度为 len = ");
scanf("%d", &len);

for(i = 0; i < len; i++)
{
printf("链表的第%d个元素：", i+1);
scanf("%d", &val);

pNew = (PNODE)malloc(sizeof(NODE));

pNew->data = val;
pNew->pNext = NULL;

pTail->pNext = pNew;
pTail = pNew;
}
return pHead;
}

//遍历链表
void travese(PNODE pHead)
{
PNODE p = pHead->pNext;  //p指向头结点

while(p)
{
printf("%d ", p->data);
p = p->pNext;
}
printf("\n");
}

//合并两个非减 单链表，至一个新的非减 单链表
PNODE union_list(PNODE pA, PNODE pB)
{
PNODE pC = (PNODE)malloc(sizeof(NODE)); //合并后链表的头结点
pC->pNext = NULL;
PNODE pTail = pC;  //指向链表C的尾节点

PNODE pa = pA->pNext;
PNODE pb = pB->pNext;

while(pa && pb)
{
if(pa->data <= pb->data)  //当前A中节点的值 大于 B中节点的值
{
pTail->pNext = pa;  //指向A中当前节点
pTail = pa;
pa = pa->pNext;
}
else
{
pTail->pNext = pb;
pTail = pb;
pb = pb->pNext;
}
}

if(pa)  //若链表A中有剩余节点
{
pTail->pNext = pa;
}
if(pb)  //若链表B中有剩余节点
{
pTail->pNext = pb;
}

return pC;
}