我的代码停止在该测试用例中工作，我认为功能Checktables中的错误，但我不确定，我无法修复错误，请帮我正确调试此代码。
image of a test case and the error
这是一个带有主.cpp
的cpp文件
#include"Header.h"
string Name;
string namess;
customer::customer()
{
name = "";
gsize = status = 0;
next = NULL;
}
customer::customer(string name1, int gsize1, int status1)
{
name = name1;
gsize = gsize1;
status = status1;
next = NULL;
}
waitinglist::waitinglist()
{
chairnum =50 ;
totalcustomers = tables = 0;
head = tail = NULL;
}
waitinglist::waitinglist(int val)
{
chairnum = 50;
totalcustomers = 0;
tables = 0;
head = tail = NULL;
}
void waitinglist::change()
{
customer*temp ;
temp = head;
cout << "enter the name: ";
cin >> namess;
while (temp != NULL)
{
if (namess == temp->name)
{
if (temp->status==2)
{
temp->status=1;
cout << "done! " << endl ;
break ;
}
}
else if (namess != temp->name)
{
temp = temp->next;
}
}
if (temp == NULL)
{
cout << "can't found! " << endl;
}
}
void waitinglist::newcustomer()
{
customer*tmp = new customer;
cout << "enter the name: "; cin >> tmp->name;
customer*tmpo=new customer;
tmpo=head ;
while (tmpo != NULL)
{
if (tmp->name != tmpo->name)
{
tmpo = tmpo->next;
}
else if (tmp->name == tmpo->name)
{
cout<<"The Name already exist! " << endl ;
cout << "enter the name: "; cin >> tmp->name;
tmpo=head;
}
}
cout << "enter the group number: "; cin >> tmp->gsize;
cout << "enter the status: "; cin >> tmp->status;
if (head == NULL) // linkedlist is empty
{
head = tail = tmp;
totalcustomers++;
}
else
{
tail->next = tmp;
tail=tail->next;
totalcustomers++;
}
}
void waitinglist::checktables()
{
float c=5.00;
customer*temp=head;
customer*found;
cout<<"enter number of tables: ";
cin >> tables ;
while (tables>=1 && temp!=NULL)
{
int x;
float y;
y=((temp->gsize)/c);
x=(temp->gsize)/c;
if (tables<y)
{
temp=temp->next;
}
else if (tables>=y)
{
if (x==y)
{
tables=tables-x ; // Correct Table!
cout<<temp->name<<endl;
}
else if (x!=y)
{
tables=tables-(x+1);
cout<<temp->name<<endl;
}
found=temp ;
delete found; // Discard
break ;
}
}
}
void waitinglist::displayall()
{
customer *tmp;
tmp = head;
if (tmp == NULL)
{
cout << "Empty!";
}
while (tmp != NULL)
{
cout << "Name: " << tmp->name <<endl;
cout << "group number: " << tmp->gsize << endl;
tmp = tmp->next;
}
cout << endl;
}
void waitinglist::diplaycustomer()
{
customer*tmp;
tmp = head;
cout << "enter the name: ";
cin >> Name;
while (tmp != NULL)
{
if (Name == tmp->name)
{
cout << "the name : " << tmp->name << endl;
cout << "the group size = " << tmp->gsize << endl;
cout << "the status = " << tmp->status << endl;
break;
}
else if (Name != tmp->name)
{
tmp = tmp->next;
}
}
if (tmp == NULL)
{
cout << "can't found!" << endl;
}
}
int main()
{
int choice;
string name1 = "";
int gsize1 = 0;
int status1 = 0;
waitinglist mylist;
cout << "Note: 1 in status means the customer not here and 2 means the customer is here.\n";
cout << "Select your option.\n\n";
cout << "(1) Add a new Customer.\n";
cout << "(2) Display information based on Name.\n";
cout << "(3) List all Names.\n";
cout << "(4) to change the status. \n" ;
cout << "(5) Check tables by name. \n";
cout << "(6) quit. \n";
do
{
cout << "\n";
cout << "Enter your choice: --> ";
cin >> choice;
if (1 <= choice && choice <= 5)
{
switch (choice)
{
case 1:
mylist.newcustomer();
break;
case 2:
mylist.diplaycustomer();
break;
case 3:
mylist.displayall();
break;
case 4:
mylist.change() ;
break;
case 5 :
mylist.checktables();
break;
default:
cout << "Invalid choice. Enter again.\n\n";
break;
}
}
else if (choice>6)
{
cout << "Invalid choice. Enter again.\n\n";
break;
}
} while (choice != 6);
return 0;
}
这是头文件.h
#include<iostream>
#include<string>
using namespace std;
class customer
{
public:
string name;
int gsize;
int status;
customer* next;
customer();
customer(string,int,int);
};
class waitinglist
{
public:
int tables; //number of occupied tables
int chairnum;
int totalcustomers;
customer*head,*tail;
waitinglist();
waitinglist(int);
void newcustomer();
void diplaycustomer();
void displayall();
void change () ;
void checktables();
};
答案 0 :(得分：2)
一个错误是您的checktables函数通过在其中一个节点上调用delete来破坏您的链接列表结构：
found = temp;
delete found; // Discard
您刚刚在上面这些行中所做的是拥有一个链接列表，其中包含一个损坏的（无效）链接。现在遍历列表的任何函数（如displaytables）现在都会破坏链接，事情开始变得混乱。
要从链接列表中删除节点，您不仅要调用delete，还要调整waitinglist中用于指向已删除节点的链接，并将其指向下一个节点删除后的一个。
将其视为真正的链 - 如果需要删除链中的某个链接，则必须将其物理删除，并将链接挂钩到下一个良好链接。你没有做这一步。
我不会为此编写代码，但这是您在程序开发早期应该看到的内容。更好的是，编写一个单链接的列表类，首先正确地添加和删除节点。测试它，然后一旦它可以成功添加和删除节点而没有错误，然后在较大的程序中使用它。