建立一个学生成绩的线性链表，对其实现插入，删除，输出，最后销毁。
#include <stdio.h>
#include <stdlib.h>
struct grade
{
int score;
struct grade *next;
};
typedef struct grade NODE; //typedef为C语言的关键字，作用是为一种数据类型定义一个新名字。
//使用typedef目的一般有两个，一个是给变量一个易记且意义明确的新名字，
//另一个是简化一些比较复杂的类型声明。
struct grade *create(); //创建链表
void insert(NODE *head,NODE *pnew,int i); //插入链表
void pdelete(NODE *head,int i); //删除列表
void display(NODE *head); //输出链表
void Pfree(NODE *head); //销毁链表
int main(int argc, char *argv[])
{
struct grade *head,*pnew;
head=create();
if(head==NULL)
return 0;
printf("输出创建的链表：");
display(head);
pnew=(NODE *)malloc(sizeof(NODE));
if(pnew==NULL)
{
printf("创建失败！");
return 0;
}
pnew->score=88;
insert(head,pnew, 3); //将新节点插入节点3的后面
printf("插入后的链表：");
display(head);
pdelete(head,3); //删除节点3
printf("删除后的链表：");
display(head);
Pfree(head);
return 0;
}
struct grade *create()
{
NODE *head,*tail,*pnew;
int score;
head=(NODE *)malloc(sizeof(NODE)); //创建头节点。
if(head==NULL) //创建失败返回
{
printf("创建失败！");
return NULL;
}
head->next=NULL; //头节点指针域置NULL
tail=head; // 开始时尾指针指向头节点
printf("输入学生成绩：");
while(1) //创建链表
{
scanf("%d",&score);
if(score<0) //成绩为负是退出循环
break;
pnew=(NODE *)malloc(sizeof(NODE)); //创建新节点
if(pnew==NULL) //创建失败返回
{
printf("创建失败！");
return NULL;
}
pnew->score=score; //新节点数据域存放输入的成绩
pnew->next=NULL; //新节点指针域置NULL
tail->next=pnew; //新节点插入到表尾
tail=pnew; //为指针指向当前的尾节点
}
return head; //返回创建链表的头指针
}
void insert(NODE *head,NODE *pnew,int i)
{
NODE *p;
int j;
p=head;
for(j=0;j<i&&p!=NULL;j++) //p指向要插入的第i个节点
p=p->next;
if(p==NULL) //节点i不存在
{
printf("与插入的节点不存在！");
return;
}
pnew->next=p->next; //插入节点的指针域指向第i个节点的后继节点
p->next=pnew; //犟第i个节点的指针域指向插入的新节点
}
void pdelete(NODE *head,int i)
{
NODE *p,*q;
int j;
if(i==0) //删除的是头指针，返回
return;
p=head;
for(j=1;j<i&&p->next!=NULL;j++)
p=p->next; //将p指向要删除的第i个节点的前驱节点
if(p->next==NULL) //表明链表中的节点不存在
{
printf("不存在！");
return;
}
q=p->next; //q指向待删除的节点
p->next=q->next; //删除节点i，也可写成p->next=p->next->next
free(q); //释放节点i的内存单元
}
void display(NODE *head)
{
NODE *p;
for(p=head->next;p!=NULL;p=p->next)
printf("%d ",p->score);
printf("
");
}
void pfree(NODE *head)
{
NODE *p,*q;
p=head;
while(p->next!=NULL) //每次删除头节点的后继节点
{
q=p->next;
p->next=q->next;
free(q);
}
free (head); //最后删除头节点
}
void Pfree(NODE *head)
{
NODE *p,*q;
p=head;
while(p->next!=NULL)
{
q=p->next;
p->next=q->next;
free(q);
}
free(p);
}
转自：http://hi.baidu.com/y%C9%D9%B0%D7y/blog/item/fa9f1c5b1525b500367abe80.html
链表是C语言中比较难，但是又比较重要的数据结构，相信有很多人在为它而头痛哦。
我做了一个链表的程序，发出来与大家共享，希望大家能用得着。
#include <stdio.h>
#include <malloc.h>
#include <conio.h>
#include <stdlib.h>
//链表单元定义，链表相关变量
struct student
{
int id;
float score;
struct student *next;
} *head,*pthis;
//输入数据创建链表
void input()
{
struct student *tmp;
printf("
请输入学生的信息以学号为0结束:
");
do
{
printf("ID 成绩
");
if((tmp=(struct student*)malloc(sizeof(struct student)))==NULL)
{
printf("
错误!不能申请所需的内存!
");
exit(0);
}
scanf("%d %f",&tmp->id,&tmp->score);
tmp->next=NULL;
if(tmp->id!=0)
{
if(head==NULL)
{
head=tmp;
pthis=head;
}
else
{
pthis->next=tmp;
pthis=pthis->next;
}
}
}
while(tmp->id!=0);
free(tmp);
}
//搜索链表找到第一个符合条件的项目输出
void search(int id)
{
printf("
查询结果
");
printf("ID 成绩
");
printf("-------------------------------
");
if(head==NULL)
{
printf("
错误!没有数据!
");
return;
}
pthis=head;
while(pthis!=NULL)
{
if(pthis->id==id)
{
printf("%d %.2f
",pthis->id,pthis->score);
return;
}
else
{
pthis=pthis->next;
}
}
printf("
没有找到!
");
}
//列表输出链表中的所有项
void list()
{
printf("
数据列表
");
printf("ID 成绩
");
printf("-------------------------------
");
if(head==NULL)
{
printf("错误,没有数据!
");
return;
}
pthis=head;
while(pthis!=NULL)
{
printf("%d %.2f
",pthis->id,pthis->score);
pthis=pthis->next;
}
}
//插入数据
void insert()
{
int i,p;
struct student *tmp;
if(head==NULL)
{
printf("
数据不存在，无法插入!
");
return;
}
printf("
请输入插入点:
");
scanf("%d",&p);
if(p<0)
{
printf("输入不合法!");
return;
}
printf("
请输入学生的信息:
ID 成绩
");
if((tmp=(struct student*)malloc(sizeof(struct student)))==NULL)
{
printf("
错误!不能申请所需的内存!
");
exit(0);
}
scanf("%d %f",&tmp->id,&tmp->score);
tmp->next=NULL;
if(tmp->id!=0)
{
pthis=head;
if(p==0)
{
tmp->next=head;
head=tmp;
}
else
{
for(i=0;i<p-1;i++)
{
if(pthis->next->next==NULL)
{
printf("
找不到插入点，您输入的数据太大!
");
return;
}
pthis=pthis->next;
}
tmp->next=pthis->next;
pthis->next=tmp;
}
}
else
{
printf("
数据无效!
");
free(tmp);
}
}
//追加数据
void append()
{
struct student *tmp;
printf("
请输入学生的信息:
ID 成绩
");
if((tmp=(struct student*)malloc(sizeof(struct student)))==NULL)
{
printf("
错误!不能申请所需的内存!
");
exit(0);
}
scanf("%d %f",&tmp->id,&tmp->score);
tmp->next=NULL;
if(tmp->id!=0)
{
if(head==NULL)
{
head=tmp;
}
else
{
pthis=head;
while(pthis->next!=NULL)
{
pthis=pthis->next;
}
pthis->next=tmp;
}
}
else
{
free(tmp);
printf("
数据无效!
");
}
}
//删除数据
void del()
{
int p,i;
struct student *tmp;
if(head==NULL)
{
printf("
没有数据，无法删除!
");
return;
}
printf("
请输入要删除的记录号:
");
scanf("%d",&p);
if(p<0)
{
printf("
输入不合法!
");
return;
}
if(p==0)
{
pthis=head;
head=pthis->next;
free(pthis);
pthis=head;
}
else
{
pthis=head;
for(i=0;i<p-1;i++)
{
pthis=pthis->next;
if(pthis->next==NULL)
{
printf("
指定记录不存在，无法删除!
");
return;
}
}
tmp=pthis->next;
pthis->next=pthis->next->next;
free(tmp);
}
}
//程序主函数
void main()
{
char command=0;
int id=0;
//主循环
do
{
printf("
菜单
");
printf("-------------------------------
");
printf(" a,输入数据
");
printf(" b,查询记录
");
printf(" c,数据列表
");
printf(" d,追加记录
");
printf(" e,插入记录
");
printf(" f,删除记录
");
printf(" g,退出系统
");
printf("-------------------------------
");
printf(" 请选择:");
command=getch();
//命令处理
switch(command)
{
case 'a':
if(head==NULL)
{
input();
break;
}
else
{
printf("
数据已经存在！
");
break;
}
case 'b':
printf("
要查询的ID:");
scanf("%d",&id);
search(id);
break;
case 'c':
list();
break;
case 'd':
append();
break;
case 'e':
insert();
break;
case 'f':
del();
break;
}
}
while(command!='g');
}
=====================
- #include <stdio.h>
- #include <string.h>
- #include <stdlib.h>
- typedef struct student
- {
- int num;
- char name[16];
- struct student *next;
- }node;
- node *creat()//创建链表
- {
- int x;
- int cycle = 1;
- char stu_name[16];
- node *head,*p,*s;
- head =(node*)malloc(sizeof(node));
- p = head;
- while(cycle)
- {
- printf("please input the student number:");
- scanf("%d",&x);
- if(x != 0)
- {
- printf("please input the student name:");
- scanf("%s",stu_name);
- // printf("STU_NAME:%s/n", stu_name);
- s = (node *)malloc(sizeof(node));
- if(NULL == s)
- {
- exit(1);
- }
- s->num = x;
- memcpy(s->name, stu_name, 16);
- p->next = s;
- p = s;
- }
- else
- cycle = 0;
- }
- head = head->next;
- p->next = NULL;
- return head;
- }
- int length(node *head)//链表测长
- {
- int n = 0;
- node *p;
- p = head;
- while(p != NULL)
- {
- n++;
- p = p->next;
- }
- return (n);
- }
- node *insert(node *head, int num, int length)//链表插入,NUM表示在第几个位置插入
- {
- int n=num;
- int i = 1;
- node *p0,*p1,*p2;
- p1 = head;
- p0 = (node *)malloc(sizeof(node));
- printf("please input the student number:");
- scanf("%d", &p0->num);
- printf("please input the student name:");
- scanf("%s", &p0->name);
- if(n == 1)//插入表头
- {
- p0->next = p1;
- head = p0;
- return (head);
- }
- while(i < n-1)//找到要插入的前置节点
- {
- p1 = p1->next;
- i++;
- }
- p2 = p1->next;
- p1->next = p0;
- p0->next = p2;
- if(n == length+1)//插入表尾
- {
- p1->next = p0;
- p0->next = NULL;
- }
- return (head);
- }
- node *delete(node *head, int location, int length)//删除链表节点
- {
- int n = location;
- int i = 1;
- node *p1,*p2;
- p1 = head;
- if(n == 1)
- {
- head = p1->next;
- free(p1);
- return (head);
- }
- while(i < n-1)//找到要删除的节点的前置节点
- {
- p1 = p1->next;
- i++;
- }
- if(n < length)
- {
- p2 = p1->next;
- p1->next = p2->next;
- free(p2);
- }
- if(n == length)
- {
- p2 = p1->next;
- p1->next = NULL;
- free(p2);
- }
- return (head);
- }
- void print(node *head)
- {
- while(head != NULL)
- {
- printf("students:%d/n", head->num);
- printf("student name: %s/n", head->name);
- head = head->next;
- }
- }
- node *invert(node *head)//链表逆置
- {
- node *p1,*p2,*p3;
- p1 = head;
- p2 = p1->next;
- while(p2)
- {
- p3 = p2->next;
- p2->next = p1;
- p1=p2;
- p2=p3;
- }
- head->next = NULL;
- head = p1;
- return (head);
- }
- int main(int argc, char **argv)
- {
- int len,insert_num,del_num;
- node *stu_node;
- stu_node = creat();
- print(stu_node);
- len = length(stu_node);
- printf("there are %d node/n", len);
- printf("what dou you want to do?/n[a]打印链表 [b]逆置链表 [c]删除节点 [d]插入节点: ");
- char ch,c;
- c = getchar();//用于清除缓冲区中的/n字符
- scanf("%c",&ch);
- switch (ch)
- {
- case 'a': print(stu_node);
- break;
- case 'b': stu_node = invert(stu_node);
- print(stu_node);
- break;
- case 'c':
- printf("which node dou you want to detele?:");
- scanf("%d", &del_num);
- stu_node = delete(stu_node, del_num, len);
- print(stu_node);
- break;
- case 'd':
- printf("which location dou you want to insert:");
- scanf("%d",&insert_num);
- stu_node = insert(stu_node , insert_num, len);
- print(stu_node);
- break;
- }
- return 0;
- }