链表操作

#define _CRT_SECURE_NO_DEPRECATE  /*取消scanf,printf不安全之类的错误提示*/
#include <stdio.h>
#include <stdlib.h>

typedef struct node
{
	int value;
	struct node* next;
}listnode;

listnode* Creat_List1(int nodenum, int *data); //最先进去的元素在最后面
listnode* Creat_List2(int nodenum, int *data); //最先进去的元素在最前面
int Get_Link_Element(listnode* head, int i); //取得头指针为head的链表中的第i个元素的值(包括第0个元素)
void Insert_List(listnode* head, int a, int i);
void Delet_List(listnode* head, int i); //删除第i个元素
listnode* Merge_TWO_Linklist(listnode *list1, listnode *list2);//合并两个有序链表

int main()
{
	int data;
	listnode *linka, *linkb, *linkc, *linkd, *linke;
	linka = (listnode*)malloc(sizeof(listnode));
	linkb = (listnode*)malloc(sizeof(listnode));
	linkc = (listnode*)malloc(sizeof(listnode));
	linkd = (listnode*)malloc(sizeof(listnode));
	linke = (listnode*)malloc(sizeof(listnode));
	int a[5] = { 1, 3, 5, 7, 9 };
	int b[3] = { 2,2, 4 };
	linka = Creat_List2(5, a);
	linkb = Creat_List2(3, b);
	Insert_List(linkb, 10, 1);
	Delet_List(linkb, 1);
	linkc=Merge_TWO_Linklist(linka, linkb);
	data = Get_Link_Element(linkb, 1);
	printf("%d\n", data);
}

//新元素总是插入到头指针后面，结果就是原先的元素一直往后移
listnode* Creat_List1(int nodenum,int *data)
{
	listnode *pc; //保存新节点
	listnode *head;
	head = (listnode*)malloc(sizeof(listnode));
	head->next = NULL; //先建立一个带头结点的单链表
	/*开始插入元素*/
	for (int i = 0; i < nodenum; i++)
	{
		pc = (listnode*)malloc(sizeof(listnode));
		pc->value = data[i];
		pc->next = head->next;
		head->next = pc;
	}
	return head;
}
//新元素插入到头指针后面，头指针一直往后移
listnode* Creat_List2(int nodenum, int *data)
{
	listnode *pc; //保存新节点
	listnode *head;
	listnode *r;//保存产生的链表
	head = (listnode*)malloc(sizeof(listnode));
	head->next = NULL; //先建立一个带头结点的单链表
	r = head;
	/*开始插入元素*/
	for (int i = 0; i < nodenum; i++)
	{
		pc = (listnode*)malloc(sizeof(listnode));
		pc->value = data[i];
		head->next = pc;
		pc->next = NULL;
		head = pc;
	}
	return r;
}

//取得头指针为head的链表中的第i个元素的值(包括第0个元素)
int Get_Link_Element(listnode* head, int i)
{
	/*创建一个扫描指针，让它指向第一个元素*/
	listnode* pc;
	int j = 0; //计数
	pc = (listnode*)malloc(sizeof(listnode));
	pc = head->next;
	while (pc != NULL && j < i) //遍历
	{
		pc = pc->next;
		j++;
	}
	if (pc == NULL || j > i) exit(-1);
	return pc->value;
}

/*
*合并两个有序链表,把list2合并到list1
*/
listnode* Merge_TWO_Linklist(listnode *list1, listnode *list2)
{
	listnode *pc1, *pc2, *pc3,*list3;
	pc1 = (listnode*)malloc(sizeof(listnode));
	pc2 = (listnode*)malloc(sizeof(listnode));
	pc3 = (listnode*)malloc(sizeof(listnode));


	pc1 = list1->next;
	pc2 = list2->next;
	pc3 = list1;
	list3 = pc3;
	while (pc1 != NULL && pc2 != NULL)
	{
		if (pc1->value <= pc2->value) {
			pc3->next = pc1;
			pc3 = pc3->next;
			pc1 = pc1->next;
		}
		else{
			pc3->next = pc2;
			pc3 = pc3->next;
			pc2 = pc2->next;
		}
	}
	if (pc1 == NULL) pc3->next = pc2;
	if (pc2 == NULL) pc3->next = pc1;
	free(list2);
	return list3;
}

void Insert_List(listnode* head, int a, int i)
{
	listnode *pc;
	listnode *s;
	pc = head->next;//令pc指向第一个元素
	int j = 1;
	while (pc != NULL && j < i)
	{
		pc = pc->next; //pc后移动
		j++;
	}
	if (pc == NULL)
	{
		printf("error\n");
		exit(-1);
	}

	s = (listnode*)malloc(sizeof(listnode));
	s->value = a;
	s->next = pc->next;
	pc->next = s;
}

//删除第i个元素
void Delet_List(listnode* head, int i)
{
	listnode *temp = NULL;
	int j = 1; //计数
	head = head->next;
	while (head != NULL && j < i)
	{
		head = head->next;
		j++;
	}
	if (head == NULL)
	{
		printf("error\n");
		exit(-1);
	}
	temp = head->next;
	head->next = temp->next;
	//head = head->next->next;
	free(temp);
}