C语言单向链表插排

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

typedef struct _List {
	int num;
	struct _List *ne;
} List; //节点结构体

int n;
List *head = NULL, *tail = NULL;

void init(int x) {
	List *temp = (List*)malloc(sizeof(List));
	temp -> num = x;
	temp -> ne = NULL;
	head = tail = temp;
} //链表初始化（第一个节点）

void insert_to_head(int x) {
	List *temp = (List*)malloc(sizeof(List));
	temp -> num = x;
	temp -> ne = head;
	head = temp;
} //头部插入

void insert_to_tail(int x) {
	List *temp = (List*)malloc(sizeof(List));
	temp -> num = x;
	temp -> ne = NULL;
	tail -> ne = temp;
	tail = temp;
} //尾部插入

void insert(int x, List *y) {
	List *temp = (List*)malloc(sizeof(List));
	temp -> num = x;
	temp -> ne = y -> ne;
	y -> ne = temp;
} //在y节点后插入

int main()
{
	scanf("%d", &n);
	for(int i = 1, x; i <= n; i++) {
		scanf("%d", &x);
		if(i == 1) init(x);
		else {
			List *pr = NULL, *temp;
			for(temp = head; temp != NULL; temp = temp -> ne) {
				if(temp -> num > x) {
					if(pr == NULL) insert_to_head(x);
					else insert(x, pr);
					break;
				}
				pr = temp;
			}
			if(temp == NULL) insert_to_tail(x);
		}
	}
	for(List *temp = head; temp != NULL; temp = temp -> ne) {
		printf("%d\n", temp -> num);
	}
	return 0;
}