求教：注释一下DElETE函数

Question

#include
#include
using namespace std;
struct item
{
char name[12];
char telnum[8];
item *next;
};
class TeleBook
{
private:
item *tbook;
int number;
public:
TeleBook()
{
tbook=NULL;
number=0;
}
void Insert();
void Delete();
void Print();
};
void TeleBook::Insert()
{
item *p;
p=new item;
if(!p)
return;
cout<<"Input name and telenumber:";
cin>>p->name>>p->telnum;
p->next=tbook;
tbook=p;//指向下一个位置；
number++;
}
void TeleBook::Delete()
{
char ch[12];
item *p,*q;
p=tbook;
cout<<"Input the name to be delete:";
cin>>ch;
while(p)
{
if(strcmp(p->name,ch)==0)
{
break;
}
q=p;
p=p->next;
}
if(p==NULL)
{
cout<<"Not found the name!"< return;
}
if(p==tbook)
{
tbook=p->next;
}
else
{
q->next=p->next;
}
number--;
cout<name<<"is deleted!"< delete p;
return;
}
void TeleBook::Print()
{
item *p;
p=tbook;
cout while(p)
{
coutname<<':'<telnum< p=p->next;
}
return;
}
int main()
{
int ch;
TeleBook myfriend;
ch=1;
cout<<"1.输入，2.删除，3.打印清单，other-退出\n";
cout<<"Please choose!";
cin>>ch;
switch(ch)
{
case 1:
myfriend.Insert();
break;
case 2:
myfriend.Delete();
break;
case 3:
myfriend.Print();
break;
}
return 0;
}

Answer 1

Delete 中有些地方可能导致崩溃，如下:

void TeleBook::Delete()
{
    char ch[12];
    item *p,*q;
    //tbook 是个链表,p 指向表头
    p=tbook;
    cout<<"Input the name to be delete:";
    cin>>ch;
    while(p)
    {
        //如果元素p中name 属性 == ch 则跳出
        if(strcmp(p->name,ch)==0)
        {
            break;
        }
        q=p;
        //访问下一个链表元素
        p=p->next;
    }
    //没有找到
    if(p==NULL)
    {
        cout<<"Not found the name!"< return;
        //这里没有找到应该直接返回
        //return ;
    }
    //如果找到的p和头元素相同
    if(p==tbook)
    {
        //删除头部的元素，修改头指针,可能存在问题,如果tbook=NULL,p=NULL,这里则崩溃
        tbook=p->next;
    }
    else
    {
        //如果没有扎到,走到这里则崩溃
        //将p从链表中剔除
        q->next=p->next;
    }
    //个数减一
    number--;
    cout<name<<"is deleted!"< delete p;
    return;
}