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我对C++相当陌生。如何显示链接列表中的特定节点？
我有这样的代码分配，我不太明白这一切，但我不得不使程序在给最终用户一个选项来调用任何部分号码和车型年/引擎没有。这是进入。
我不知道如何去做这个任务...也许有每种节点的某种id，所以我可以回想起来？
或者是我使用数组或矢量数据结构重写程序的唯一选择吗？
#include <iostream>
using namespace std;
typedef unsigned long ULONG;
typedef unsigned short USHORT;
// **************** Part ************
// Abstract base class of parts
class Part
{
friend void showPart();
public:
Part():itsPartNumber(1) {}
Part(ULONG PartNumber):itsPartNumber(PartNumber){}
virtual ~Part(){};
ULONG GetPartNumber() const { return itsPartNumber; }
virtual void Display() const =0; // must be overridden
private:
ULONG itsPartNumber;
};
// implementation of pure virtual function so that
// derived classes can chain up
void Part::Display() const
{
cout << "\nPart Number: " << itsPartNumber << endl;
}
// **************** Car Part ************
class CarPart : public Part
{
friend void showPart();
public:
CarPart():itsModelYear(94){}
CarPart(USHORT year, ULONG partNumber);
virtual void Display() const
{
Part::Display(); cout << "Model Year: ";
cout << itsModelYear << endl;
}
private:
USHORT itsModelYear;
};
CarPart::CarPart(USHORT year, ULONG partNumber):
itsModelYear(year),
Part(partNumber)
{}
// **************** AirPlane Part ************
class AirPlanePart : public Part
{
friend void showPart();
public:
AirPlanePart():itsEngineNumber(1){};
AirPlanePart(USHORT EngineNumber, ULONG PartNumber);
virtual void Display() const
{
Part::Display(); cout << "Engine No.: ";
cout << itsEngineNumber << endl;
}
private:
USHORT itsEngineNumber;
};
AirPlanePart::AirPlanePart(USHORT EngineNumber, ULONG PartNumber):
itsEngineNumber(EngineNumber),
Part(PartNumber)
{}
// **************** Part Node ************
class PartNode
{
public:
PartNode (Part*);
~PartNode();
void SetNext(PartNode * node) { itsNext = node; }
PartNode * GetNext() const;
Part * GetPart() const;
private:
Part *itsPart;
PartNode * itsNext;
};
// PartNode Implementations...
PartNode::PartNode(Part* pPart):
itsPart(pPart),
itsNext(0)
{}
PartNode::~PartNode()
{
delete itsPart;
itsPart = 0;
delete itsNext;
itsNext = 0;
}
// Returns NULL if no next PartNode
PartNode * PartNode::GetNext() const
{
return itsNext;
}
Part * PartNode::GetPart() const
{
if (itsPart)
return itsPart;
else
return NULL; //error
}
// **************** Part List ************
class PartsList
{
public:
PartsList();
~PartsList();
// needs copy constructor and operator equals!
Part* Find(ULONG & position, ULONG PartNumber) const;
ULONG GetCount() const { return itsCount; }
Part* GetFirst() const;
static PartsList& GetGlobalPartsList()
{
return GlobalPartsList;
}
void Insert(Part *);
void Iterate(void (Part::*f)()const) const;
Part* operator[](ULONG) const;
private:
PartNode * pHead;
ULONG itsCount;
static PartsList GlobalPartsList;
};
PartsList PartsList::GlobalPartsList;
// Implementations for Lists...
PartsList::PartsList():
pHead(0),
itsCount(0)
{}
PartsList::~PartsList()
{
delete pHead;
}
Part* PartsList::GetFirst() const
{
if (pHead)
return pHead->GetPart();
else
return NULL; // error catch here
}
Part * PartsList::operator[](ULONG offSet) const
{
PartNode* pNode = pHead;
if (!pHead)
return NULL; // error catch here
if (offSet > itsCount)
return NULL; // error
for (ULONG i=0;i<offSet; i++)
pNode = pNode->GetNext();
return pNode->GetPart();
}
Part* PartsList::Find(ULONG & position, ULONG PartNumber) const
{
PartNode * pNode = 0;
for (pNode = pHead, position = 0;
pNode!=NULL;
pNode = pNode->GetNext(), position++)
{
if (pNode->GetPart()->GetPartNumber() == PartNumber)
break;
}
if (pNode == NULL)
return NULL;
else
return pNode->GetPart();
}
void PartsList::Iterate(void (Part::*func)()const) const
{
if (!pHead)
return;
PartNode* pNode = pHead;
do
(pNode->GetPart()->*func)();
while (pNode = pNode->GetNext());
}
void PartsList::Insert(Part* pPart)
{
PartNode * pNode = new PartNode(pPart);
PartNode * pCurrent = pHead;
PartNode * pNext = 0;
ULONG New = pPart->GetPartNumber();
ULONG Next = 0;
itsCount++;
if (!pHead)
{
pHead = pNode;
return;
}
// if this one is smaller than head
// this one is the new head
if (pHead->GetPart()->GetPartNumber() > New)
{
pNode->SetNext(pHead);
pHead = pNode;
return;
}
for (;;)
{
// if there is no next, append this new one
if (!pCurrent->GetNext())
{
pCurrent->SetNext(pNode);
return;
}
// if this goes after this one and before the next
// then insert it here, otherwise get the next
pNext = pCurrent->GetNext();
Next = pNext->GetPart()->GetPartNumber();
if (Next > New)
{
pCurrent->SetNext(pNode);
pNode->SetNext(pNext);
return;
}
pCurrent = pNext;
}
}
int main()
{
PartsList pl = PartsList::GetGlobalPartsList();
Part * pPart = 0;
ULONG PartNumber;
USHORT value;
ULONG choice;
while (1)
{
cout << "(0)Quit (1)Car (2)Plane: ";
cin >> choice;
if (!choice)
break;
cout << "New PartNumber?: ";
cin >> PartNumber;
if (choice == 1)
{
cout << "Model Year?: ";
cin >> value;
pPart = new CarPart(value,PartNumber);
}
else
{
cout << "Engine Number?: ";
cin >> value;
pPart = new AirPlanePart(value,PartNumber);
}
pl.Insert(pPart);
}
void (Part::*pFunc)()const = &Part::Display;
pl.Iterate(pFunc);
cout << "\n\n\nThere are " << pl.GetCount() << " items in the list" << endl;
return 0;
}
我试过在PartsList类中使用Find（）。 Find（）是否获取partnumber并返回零件的地址？
我写这篇取消引用检索到的地址，但它给我的错误no match for 'operator<<' in 'std::cout << * show'：
int findnumber;
ULONG position;
cout << "Enter Partnumber" << endl;
cin >> findnumber;
Part* show = pl.Find(position, findnumber);
cout << *show;
我这样做都是错的？ D：请给我看看......
如果你更清楚你的问题会更好 – 0decimal0