Why

最近学习的数据结构与算法，作为小白自然是从基础开始，也即线性结构-单链表

一、相关函数

List* creatlist(int n)				//产生链表的函数，n决定链表长度
{
	List* p，* head，* q = NULL;
	int a = 0;
	for (int i = 0; i < n; i++){
		if(scanf("%d", &a));
		p = (List*)malloc(sizeof(List));
		if (p != NULL){
			p->data = a;
			p->next = NULL;
		}
		if (head == NULL){
			head = p;
			q = p;
		}		
		else{
			q->next = p;
			q = p;
		}
	}
	return head;	
}

void showlist(List* L1)					//打印链表的函数
{
	List* p = NULL;
	p = L1;
	while (p->next != NULL){
		printf("%d ", p->data);
		p = p->next;
	}
	printf("%d ", p->data);

}

List* insertlist(List* L1, int m, int n)		//函数实现链表元素的插入,m控制所插入元素的个数，n用来控制插入的节点
{
	List* p = L1;
	for (int i = 0; i < n-1; i++){
		p = p->next;	
	}
	List* q = NULL;
	q = creatlist(m);		//产生的插入链表以q为头
	List* t = NULL;
	t = q;
	while (t->next != NULL){
		t = t->next;
	}
	t->next = p->next;
	p->next = q;
	return L1;
}

List* deletelist(List* L1, int n)		//函数实现链表元素的，第n个节点的删除
{
	List* t, *q = NULL;
	List* p = L1;
	for(int i = 0; i < n-1; i++){
		p = p->next;
	};
	if(p){ 
		q = p->next;
		t = q->next;
		p->next = t;
	}
	return L1;
}

List* link_reversed_order(List* p_head)       //实现链表的倒序
{
	List* pf = NULL, * pb = NULL, * tmp = NULL;
	pf = p_head;
	if (p_head == NULL) {
		printf("链表为空，不需要逆序！\n");
		return p_head;
	}
	else if (p_head->next == NULL) {
		printf("链表只有一个节点，不需要逆序！\n");
		return p_head;
	}
	else {
		pb = pf->next;
		p_head->next = NULL;
		while (pb != NULL){
			tmp = pb;
			pb = pb->next;
			tmp->next = pf;
			pf = tmp;
		}
		p_head = pf;
		return p_head;
	}
}

二、程序主体及运行情况

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX 20
typedef int Elemtype;
struct number {
	Elemtype data;
	struct number* next;
};
typedef struct number List;
List* creatlist(int n);					//产生链表的函数，n决定链表长度
void showlist(List* L1);				//打印链表的函数, n用来控制打印的初始位置
List* insertlist(List* L1, int m, int n);//函数实现链表元素的插入,m控制所插入元素的个数，n用来控制插入的节点
List* deletelist(List* L1, int n);		//函数实现链表元素的，第n个节点的删除
List* link_reversed_order(List* p_head);//函数实现链表元素的倒序输出
int main(void)
{
	int a, b, m, n = 0;
	List* L, * L1, * L2, * L3 = NULL;
	printf("输入所要创建的链表元素的个数：\n");
	scanf("%d", &a);
	printf("现在依次输入链表元素：\n");
	L = creatlist(a);
	printf("请输入插入元素的节点：\n");
	scanf("%d", &n);
	printf("请输入插入元素的个数：\n");
	scanf("%d", &m);
	printf("现在依次输入所要插入的元素：\n");
	L1 = insertlist(L, m, n);
	printf("插入元素后的链表为：\n");
	showlist(L1);
	printf("\n");
	printf("输入要删除的节点：\n");
	scanf("%d", &b);
	L2 = deletelist(L1, b);
	printf("删除节点后的链表为：\n");
	showlist(L2);
	printf("\n");
	printf("输出上一链表的倒序结果为：\n");
	L3 = link_reversed_order(L2);
	showlist(L3);
	return 0;
}