单链表

/*用链表实现学生成绩信息的管理*/
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
struct stud_node
{
    int num;
    char name[20];
    int score;
    struct stud_node*next;
};

/*函数声明*/
struct stud_node *Creat_Stu_Doc();//新建链表
struct stud_node *InsertDoc(struct stud_node *head,struct stud_node *stud);//插入
struct stud_node *DeleteDoc(struct stud_node *head,int num);//删除
void Print_Stu_Doc(struct stud_node *head);//遍历

/*主函数*/
int main()
{
    struct stud_node *head,*p;
    int choice,num,score;
    char name[20];
    int size=sizeof(struct stud_node);

    do 
    {
        printf("1.Creat 2.Insert 3.Delete 4.Print 0.Exit 
");
        scanf("%d",&choice);
        switch (choice)
        {
        case 1:
            head=Creat_Stu_Doc();
            break;
        case 2:
            printf("Input num,name and score:
");
            scanf("%d%s%d",&num,&name,&score);
            p=(struct stud_node*)malloc(size);
            p->num=num;
            strcpy(p->name,name);
            p->score=score;
            head=InsertDoc(head,p);
            break;
        case 3:
            printf("Input num:
");
            scanf("%d",&num);
            head=DeleteDoc(head,num);
            break;
        case 4:
            Print_Stu_Doc(head);
            break;
        case 0:
            break;
        }
    } while (choice!=0);

    return 0;
}

//新建链表
struct stud_node *Creat_Stu_Doc()
{
    struct stud_node *head,*p;
    int num,score;
    char name[20];
    int size=sizeof(struct stud_node);

    head=NULL;
    printf("Input num,name and score:
");
    scanf("%d%s%d",&num,&name,&score);
    while (num!=0)
    {
        p=(struct stud_node*)malloc(size);
        p->num=num;
        strcpy(p->name,name);
        p->score=score;
        head=InsertDoc(head,p);
        scanf("%d%s%d",&num,&name,&score);
    }
    return head;
}

//插入操作
struct stud_node *InsertDoc(struct stud_node *head,struct stud_node *stud)
{
    struct stud_node *ptr,*ptr1,*ptr2;

    ptr2=head;
    ptr=stud;//ptr指向待插入的新的学生记录结点
    //原链表为空时的插入
    if (head==NULL)
    {
        head=ptr;            //新插入结点成为头结点
        head->next=NULL;
    }
    else                    //原链表不为空时的插入
    {
        while ((ptr->num>ptr2->num)&&(ptr2->next!=NULL))
        {
            ptr1=ptr2;                    //ptr1，ptr2各后移一个结点
            ptr2=ptr2->next;
        }
        if (ptr->num<=ptr2->num)        //在ptr1与ptr2之间插入新结点
        {
            if(head==ptr2)
                head=ptr;
            else
                ptr1->next=ptr;
        }
        else                //新插入结点成为尾结点
        {
            ptr2->next=ptr;
            ptr->next=NULL;
        }
    }
    return head;
}

//删除操作
struct stud_node *DeleteDoc(struct stud_node *head,int num)
{
    struct stud_node *ptr1,*ptr2;

    //要被删除结点为表头结点
    while (head!=NULL&&head->num==num)
    {
        ptr2=head;
        head=head->next;
        free(ptr2);
    }
    if(head==NULL)        //链表空
        return NULL;
    //要被删除结点为非表头结点
    ptr1=head;
    ptr2=head->next;    //从表头的下一个结点搜索所有符合删除要求的结点
    while(ptr2!=NULL)
    {
        if (ptr2->num==num)        //ptr2所指结点符合删除要求
        {
            ptr1->next=ptr2->next;
            free(ptr2);
        }
        else
            ptr1=ptr2;        //ptr1后移一个结点
        ptr2=ptr1->next;    //ptr2指向ptr1的后一个结点
    }
    return head;
}

//遍历操作
void Print_Stu_Doc(struct stud_node *head)
{
    struct stud_node *ptr;
    if (head==NULL)
    {
        printf("
No Records
");
        return;
    }
    printf("
The Students' Records Are:
");
    printf("Num	 Name	 Score
");
    for(ptr=head;ptr!=NULL;ptr=ptr->next)
        printf("%d	%s	%d
",ptr->num,ptr->name,ptr->score);
}