#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct link
{
    char name[20];
    char num[50];
    struct link *next;
};

struct link *Insert(struct link *head)          //插入输入的节点
{
    char name2[20];
    struct link *pr = head, *p = head;
    p = (struct link *)malloc(sizeof(struct link));
    p ->next = NULL;
    scanf("nsert %s %s behind %s",p->name,p->num,name2);
    int q;
    q = strcmp(name2,"Nobody");
    if (q == 0) head = p;
    else
    {
        q=strcmp(pr->name,name2);
        while (q!=0 && pr->next != NULL)
        {
            pr = pr->next;
            q=strcmp(pr->name,name2);
        }
        if (q == 0)
        {
            struct link *temp = NULL;
            temp = pr->next;
            pr->next = p;
            p->next = temp;
        }
    }
    return head;
}
struct link *Delete(struct link *head)   //删除节点
{
    char name2[20];
    scanf("elete %s",name2);
    struct link *p = head, *pr = head;
    int m;
    m=strcmp(p->name,name2);
    while(m != 0 && p->next != NULL);
    {
        pr = p;
        p = p->next;
        m = strcmp(p->name,name2);
    }
    if (m == 0)
    {
        if (p == head)
        {
            head = p->next;
        }
        else
        {
            pr->next = p->next;
        }
        free(p);
    }
    return head;
}
void Print(struct link *head)            //显示电话本
{
    struct link *p = head;
    while (p != NULL)
    {
        printf("%s ",p->name);
        printf("%s",p->num);
        printf("\n");
        p = p->next;
    }
    fflush(stdin);
}
void DELETE(struct link *head)              //清空内存
{
    struct link *p = head,  *pr = NULL;
    while (p != NULL)
    {
        pr = p;
        p = p->next;
        free(pr);
    }
}


int main()
{
    struct link *head = NULL;
    char order;
    scanf("%c",&order);
    while(order != 'E')
    {
        if (order == 'I')
        {
            head = Insert(head);
        }
        else
        {
            if (order == 'D')
            {
                head = Delete(head);
            }
            else
            {
                if( order == 'P')
                {
                    Print(head);
                }
            }
        }
        order = '\0';
        scanf("%c",&order);
    }
    DELETE(head);
    return 0;
}

用例为
Input：

Insert LiLei 14068888 behind Nobody
Insert Joker 04517999 behind LiLei
Insert Healer 987213 behind Joker
Print
Delete LiLei
Print
End

Output：

LiLei 14068888
Joker 04517999
Healer 987213
Joker 04517999
Healer 987213

用Delete函数的之后，程序就不能再往下进行了。
调试的时候提示运行时错误。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct link
{
    char name[20];
    char num[50];
    struct link *next;
};

struct link *Insert(struct link *head)          //插入输入的节点
{
    char name2[20];
    struct link *pr = head, *p = head;
    p = (struct link *)malloc(sizeof(struct link));
    p->next = NULL;
    scanf("nsert %s %s behind %s", p->name, p->num, name2);
    int q;
    q = strcmp(name2, "Nobody");
    if (q == 0) head = p;
    else
    {
        q = strcmp(pr->name, name2);
        while (q != 0 && pr->next != NULL)
        {
            pr = pr->next;
            q = strcmp(pr->name, name2);
        }
        if (q == 0)
        {
            struct link *temp = NULL;
            temp = pr->next;
            pr->next = p;
            p->next = temp;
        }
    }
    return head;
}
struct link *Delete(struct link *head)   //删除节点
{
    char name2[20];
    scanf("elete %s", name2);
    struct link *p = head, *pr = head;
    int m;
    m = strcmp(p->name, name2);
    while (m != 0 && p->next != NULL);
    {
        pr = p;
        p = p->next;
        m = strcmp(p->name, name2);
    }
    if (m == 0)
    {
        if (p == head)
        {
            head = p->next;
        }
        else
        {
            pr->next = p->next;
        }
        free(p);
    }
    return head;
}
void Print(struct link *head)            //显示电话本
{
    struct link *p = head;
    while (p != NULL)
    {
        printf("%s ", p->name);
        printf("%s", p->num);
        printf("\n");
        p = p->next;
    }
    fflush(stdin);
}
void DELETE(struct link *head)              //清空内存
{
    struct link *p = head, *pr = NULL;
    while (p != NULL)
    {
        pr = p;
        p = p->next;
        free(pr);
    }
}


int main()
{
    struct link *head = NULL;
    char order;
    scanf("%c", &order);
    while (order != 'E')
    {
        if (order == 'I')
        {
            head = Insert(head);
        }
        else
        {
            if (order == 'D')
            {
                head = Delete(head);
            }
            else
            {
                if (order == 'P')
                {
                    Print(head);
                }
            }
        }
        order = '\0';
        scanf(" %c", &order);//这里会收到缓冲区的回车，所以需要改一下
    }
    DELETE(head);
    return 0;
}

加了fflush(stdin)之后还是不行…

Delete失效的问题：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct link
{
    char name[20];
    char num[50];
    struct link *next;
};

struct link *Insert(struct link *head)          //插入输入的节点
{
    char name2[20];
    struct link *pr = head, *p = head;
    p = (struct link *)malloc(sizeof(struct link));
    p->next = NULL;
    scanf("nsert %s %s behind %s", p->name, p->num, name2);
    int q;
    q = strcmp(name2, "Nobody");
    if (q == 0) head = p;
    else
    {
        q = strcmp(pr->name, name2);
        while (q != 0 && pr->next != NULL)
        {
            pr = pr->next;
            q = strcmp(pr->name, name2);
        }
        if (q == 0)
        {
            struct link *temp = NULL;
            temp = pr->next;
            pr->next = p;
            p->next = temp;
        }
    }
    return head;
}
struct link *Delete(struct link *head)   //删除节点
{
    char name2[20];
    scanf("elete %s", name2);
    struct link *p = head, *pr = head;
    int m;
    m = strcmp(p->name, name2);
    while (m != 0)
    {
        pr = p;
        p = p->next;
        m = strcmp(p->name, name2);
        if (p->next == NULL)
        {
            break;
        }
    }
    if (m == 0)
    {
        if (p == head)
        {
            head = p->next;
        }
        else
        {
            pr->next = p->next;
        }
        free(p);
    }
    return head;
}
void Print(struct link *head)            //显示电话本
{
    struct link *p = head;
    while (p != NULL)
    {
        printf("%s ", p->name);
        printf("%s", p->num);
        printf("\n");
        p = p->next;
    }
    fflush(stdin);
}
void DELETE(struct link *head)              //清空内存
{
    struct link *p = head, *pr = NULL;
    while (p != NULL)
    {
        pr = p;
        p = p->next;
        free(pr);
    }
}


int main()
{
    struct link *head = NULL;
    char order;
    scanf("%c", &order);
    while (order != 'E')
    {
        if (order == 'I')
        {
            head = Insert(head);
        }
        else
        {
            if (order == 'D')
            {
                head = Delete(head);
            }
            else
            {
                if (order == 'P')
                {
                    Print(head);
                }
            }
        }
        order = '\0';
        scanf(" %c", &order);
    }
    DELETE(head);
    return 0;
}

谢谢大神！我用code blocks自己编译通过了，但是测试代码的系统编译器好像不太一样，一直显示运行时错误，请问可能是什么原因呢？

测试的用例是什么？我试试。我只是用你之前给的用例试了。

我也不知道用例是什么老师不告诉……

有没有可能
Insert LiLei 14068888 behind Nobody
 Delete LiLei
 Insert Joker 04517999 behind LiLei
这样的话判断起来比较麻烦了。各种条件纠缠在一起

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct link
{
    char name[20];
    char num[50];
    struct link *next;
};

struct link *Insert(struct link *head)          //插入输入的节点
{
    char name2[20];
    struct link *pr = head, *p = head;
    p = (struct link *)malloc(sizeof(struct link));
    p->next = NULL;
    scanf("nsert %s %s behind %s", p->name, p->num, name2);
    int q;
    q = strcmp(name2, "Nobody");
    if (q == 0) head = p;
    else
    {
        q = strcmp(pr->name, name2);
        while (q != 0 && pr->next != NULL)
        {
            pr = pr->next;
            q = strcmp(pr->name, name2);
        }
        if (q == 0)
        {
            struct link *temp = NULL;
            temp = pr->next;
            pr->next = p;
            p->next = temp;
        }
    }
    return head;
}
struct link *Delete(struct link *head)   //删除节点
{
    char name2[20];
    scanf("elete %s", name2);
    struct link *p = head, *pr = head;
    int m;
    if (p == NULL)
    {
        return head;
    }
    m = strcmp(p->name, name2);
    while (m != 0)
    {
        pr = p;
        p = p->next;
        m = strcmp(p->name, name2);
        if (p->next == NULL)
        {
            break;
        }
    }
    if (m == 0)
    {
        if (p == head)
        {
            head = p->next;
        }
        else
        {
            pr->next = p->next;
        }
        free(p);
    }
    return head;
}
void Print(struct link *head)            //显示电话本
{
    struct link *p = head;
    while (p != NULL)
    {
        printf("%s ", p->name);
        printf("%s", p->num);
        printf("\n");
        p = p->next;
    }
    fflush(stdin);
}
void DELETE(struct link *head)              //清空内存
{
    struct link *p = head, *pr = NULL;
    while (p != NULL)
    {
        pr = p;
        p = p->next;
        free(pr);
    }
}


int main()
{
    struct link *head = NULL;
    char order;
    scanf("%c", &order);
    while (order != 'E')
    {
        if (order == 'I')
        {
            head = Insert(head);
        }
        else
        {
            if (order == 'D')
            {
                head = Delete(head);
            }
            else
            {
                if (order == 'P')
                {
                    Print(head);
                }
            }
        }
        order = '\0';
        scanf(" %c", &order);
    }
    DELETE(head);
    return 0;
}

系统提示我的是 程序执行了非法操作。一般是试图访问不可访问的内存，或试图执行无权执行的指令