链表

实例：学生管理 学号 成绩 若学号为0则程序停止 建立一个链表

# include <stdio.h>
# include <malloc.h>

struct stu_node* creat(void);  /*函数声明*/
void list(struct stu_node* head);

struct stu_node  /*建立一个结构体*/
{
	int num;
	float score;
	struct stu_node* next;   /*next是struct stu_node*类型的 是指针变量*/
};
#define LEN sizeof(struct stu_node)  /*宏定义一个结构体的长度用于下面的动态链表*/


int main()
{
	struct stu_node* head;
	head = creat();
	list(head);
	return 0;
}

struct stu_node* creat(void)  /*struct stu_node*代表函数的返回值是这个类型的，(void)代表没有形参*/
{
	struct stu_node* p1 = NULL;   /*这三个都是存放地址的指针变量*/
	struct stu_node* p2 = NULL;
	struct stu_node* head = NULL;
	int n;
	float s;
	scanf_s("%d%f", &n, &s);
	while (n != 0)   /*实例，学号不等于0*/
	{
		p1 = (struct stu_node*)malloc(LEN);  /*既建立了一个节点，又把这个节点的地址赋给p1。多次循环即建立出一个链表*/
		p1->num = n; p1->score = s;     /*赋值*/
		if (head == NULL)    /*第一次会走这个*/
			head = p1;
		else     /*除第一次之外走这个*/
			p2->next = p1;
		p2 = p1;
		scanf_s("%d%f", &n, &s);
	}
	p2->next = NULL; /*将尾节点的next赋为NULL*/
	return head;  /*返回头指针，因为头指针代表着这个链表，而且后边的链表的删除会有一种情况必须要返回头指针*/
}


void list(struct stu_node* head)    /*输出链表中的所有节点*/
{
	struct stu_node* p;           /*存储*/
	if (head == NULL)
		printf("此链表为空！\n");
	else
	{
		printf("链表内容如下：\n");
		p = head;               
		while (p != NULL)   /*循环的赋值然后输出*/
		{
			printf("%d %f\n", p->num, p->score);
			p = p->next;
		}
	}
}

仍然是实例 链表要多写 多重复是好事 多了个删除功能

# include <stdio.h>
# include <malloc.h>

struct stu_node* creat(void);
void list(struct stu_node* head);
struct stu_node* del(struct stu_node* head, int num);

struct stu_node
{
	int num;
	float score;
	struct stu_node* next;
};
#define LEN sizeof(struct stu_node)


int main()
{
	int num;
	struct stu_node* head;
	head=creat();
	printf("请输入想要删除的学生信息所对应的学号：");
	scanf_s("%d", &num);  /*n是要删除的学号对应的节点*/
	head=del(head, num);
	list(head);
	return 0;
}

struct stu_node* creat(void)
{
	struct stu_node* p1=NULL;
	struct stu_node* p2=NULL;
	struct stu_node* head=NULL;
	int n;  float s;
	printf("请输入学生的学号和成绩，中间用空格隔开，若学号为0则停止\n");
	scanf_s("%d%f", &n, &s);
	while (n != 0)
	{
		p1 = (struct stu_node*)malloc(LEN);
		p1->num = n;  p1->score = s;
		if (head == NULL)
			head = p1;
		else
			p2->next = p1;
		p2 = p1;
		scanf_s("%d%f", &n, &s);
	}
	p2->next = NULL;
	return head;
}

void list(struct stu_node* head)
{
	struct stu_node* p;
	if (head == NULL)
		printf("空指针\n");
	else
	{
		printf("链表的内容如下：\n");
		p = head;
		while (p != NULL)
		{
			printf("%d %f\n", p->num, p->score);
			p = p->next;
		}
	}
}

struct stu_node* del(struct stu_node* head, int num)
{
	struct stu_node* p1=NULL;
	struct stu_node* p2=NULL;
	if (head == NULL)
		printf("链表为空无法进行删除！\n");
	else
	{
		p1 = head;
		while ((num != p1->num) && (p1->next != NULL))
		{
			p2 = p1;
			p1 = p1->next;
		}
		if (p1->num == num)
		{
			if (p1 == head)
				head = p1->next;
			else
				p2->next = p1->next;
			free(p1);
			printf("该节点已经删除\n");
		}
		else
			printf("链表中不存在该节点，无法删除！\n");
	}
	return head;
}

链表的插入 所有都不是复制粘贴，为的是熟练，但插入部分还要继续研究熟悉

# include <stdio.h>
# include <malloc.h>
struct stu_node* insert(struct stu_node* head);
struct stu_node* creat(void);
void list(struct stu_node* head);
struct stu_node
{
	int num;
	float score;
	struct stu_node* next;
};
#define LEN sizeof(struct stu_node)

int main()
{
	struct stu_node* head;
	head = creat();
	insert(head);
	list(head);
	return 0;
}

struct stu_node* creat(void)
{
	struct stu_node* p1=NULL;
	struct stu_node* p2=NULL;
	struct stu_node* head=NULL;
	int n;  float s;
	scanf_s("%d%f", &n, &s);
	while (n != 0)
	{
		p1 = (struct stu_node*)malloc(LEN);
		p1->num = n;
		p1->score = s;
		if (head == NULL)
			head = p1;
		else
			p2->next = p1;
		p2 = p1;
		scanf_s("%d%f", &n, &s);
	}
	p2->next = NULL;
	return head;
}

void list(struct stu_node* head)
{
	struct stu_node* p;
	if (head == NULL)
		printf("空链表\n");
	else
	{
		printf("链表的内容如下：\n");
		p = head;
		while (p != NULL)
		{
			printf("%d %f\n", p->num, p->score);
			p = p->next;
		}
	}
}

struct stu_node* insert(struct stu_node* head)
{
	struct stu_node* p0;
	struct stu_node* p1;
	struct stu_node* p2;
	p0 = (struct stu_node*)malloc(LEN);
	p0->next = NULL;
	printf("请输入要插入的学号和成绩：\n");
	scanf_s("%d%f", &p0->num, &p0->score);
	getchar();
	if (head == NULL)
		head = p0;
	else
	{
		p1 = head;
		while ((p0->num > p1->num) && (p1->next != NULL))
		{
			p2 = p1;
			p1 = p1->next;
		}
		if (p0->num <= p1->num)
		{
			if (head == p1)
				head = p0;
			else
				p2->next = p0;
			p0->next = p0;
		}
		else
			p1->next = p0;
	}
	return head;
}