C实现单链表直接选择排序

/****************************
单链表直接选择排序
*******************************/
#include<stdio.h>
#include<stdlib.h>
struct node
{
int num;
struct node *next;
};
struct node *head=NULL;
cre_list() //初始化结点
{
head = (struct node *)malloc(sizeof(struct node));
head->num=0;
head->next = NULL;
}
add_node(int num) //插入结点
{
struct node *ptr = (struct node *)malloc(sizeof(struct node));
ptr->num = num;
ptr->next = head->next;
head->next=ptr;
}

display_node() //遍历链表
{
struct node *p = head->next;
do
{
printf("%d\t",p->num);
p = p->next;
}while(p != NULL);
printf("\n");
}

select_insert()
{
int min=0;
int tmp=0;
struct node *p,*q,*M;
p=q=M=head;
while(p->next!=NULL)
{
M=q=p->next;
min=q->num;

while(q!=NULL)
{
if(q->num < min)
{
M=q;
min=q->num;
}
q=q->next;
}
if(p->next!=M)
{
tmp=p->next->num;
p->next->num=M->num;
M->num=tmp;
}
p=p->next;
}
}

int main()
{
int i;
int a[10]={23,41,77,12,98,25,6,97,55,38};
cre_list();
for(i=0;i<10;i++)
{
add_node(a[i]);
}
display_node();
select_insert();
display_node();

return 0;
}