C++ Syntaxe, Aide

Question

J'ai écrit un programme court

#include <iostream.h> 

class node 
{ 
public: 
    int value;   //value stored in the node 
    node *next;   //pointer to next node 
    node *prev;   //pointer to previous node 
}; 

class dlist 
{ 
public: 
    node *front;  //pointer to front of list 
    node *back;  //pointer to back of list 

    dlist() 
    { 
     front=NULL; 
     back=NULL; 
    } 

    void insertFront(int value);    
    void insertBack(int value); 
    void removeFront(); 
    void removeBack(); 
    void insertBefore(int value,node *nodeB); 
    void insertAfter(int value,node *nodeA); 
    void removeBefore(node *nodeB); 
    void removeAfter(node *nodeA); 
    void removeNode(node *newNode); 
    void printDListFront(); 
    void printDListBack(); 
}; 

//insert a node before nodeB 
void dlist::insertBefore(int value,node *nodeB)  
{ 
    node *newNode; 
    newNode=new node(); 
    newNode->prev=nodeB->prev; 
    newNode->next =nodeB; 
    newNode->value =value; 
    if(nodeB->prev==NULL) 
    { 
     this->front=newNode; 
    } 
    nodeB->prev=newNode; 

} 

//insert a node before the front node 
void dlist::insertFront (int value) 
{ 
    node *newNode; 
    if(this->front==NULL) 
    { 
     newNode=new node(); 
     this->front=newNode; 
     this->back =newNode; 
     newNode->prev=NULL; 
     newNode->next=NULL; 
     newNode->value=value; 

    } 
    else 
    { 
     insertBefore(value,this->front); 
    } 
} 

//insert a node after nodeB 
void dlist::insertAfter(int value,node *nodeB) 
{ 
    node *newNode; 
    newNode=new node(); 
    newNode->next= nodeB->next ; 
    newNode->prev =nodeB; 
    newNode->value =value; 

    if(nodeB->next==NULL) 
    { 
     cout<<"\n "<< endl; 
     this->back =newNode; 
    } 
    nodeB->next=newNode; 
    cout<<"2"<<endl; 
} 
//insert a node after the last node 
void dlist::insertBack (int value) 
{   
    if(this->back==NULL) 
    { 
     cout<<"insert at back"; 
     insertFront(value); 
    } 
    else 
    { 
     cout<<"insert at back"; 
     insertAfter(value,this->back ); 
    } 
} 

//remove the front node 
void dlist::removeFront() 
{ 
    removeNode(this->front); 
} 

//remove a back node 
void dlist::removeBack () 
{ 
    removeNode(this->back); 

} 

//remove before a node 
void dlist::removeBefore(node *nodeB) 
{ 

    if(nodeB->prev==this->front) 
    { 
     this->front=nodeB; 
     this->front->prev=NULL; 
    } 
    else 
    { 
     removeNode(nodeB->prev); 
    } 
} 

//remove after a node 
void dlist::removeAfter(node *nodeA) 
{ 
    if(nodeA->next==this->back) 
    { 
     this->back=nodeA; 
     this->back->next=NULL; 
    } 
    else 
    { 
     removeNode(nodeA->next); 
    } 
} 

//remove a perticular node 
void dlist::removeNode(node *nodeToRemove) 
{ 
    if(nodeToRemove==this->front) 
    { 
     this->front=this->front->next; 
     this->front->prev=NULL; 
    } 
    else if (nodeToRemove==this->back) 
    { 
     this->back=this->back->prev; 
     this->back->next=NULL ; 
    } 
    else 
    { 
     nodeToRemove->prev->next=nodeToRemove->next; 
     nodeToRemove->next->prev=nodeToRemove->prev; 
    } 
} 

//Print the list from front 
void dlist::printDListFront() 
{ 
    node* curr2; 
    curr2= this->front; 
    cout<<"\n-----\n"; 
    cout<<"Queue\n"; 
    cout<<"-----\n"; 
    //cout<<"size:"<<getQueueSize()<<endl; 
    while(curr2!=NULL) 
    { 
     cout<<" |"<<curr2->value<<"|"; 
     curr2=curr2->next; 
    } 
    cout<<endl; 
}// print the Double Linked List from front 


// print the Double Linked List from backwards 
void dlist::printDListBack() 
{ 
    node* curr2; 
    curr2= this->back; 
    cout<<"\n-----\n"; 
    cout<<"Queue\n"; 
    cout<<"-----\n"; 
    //cout<<"size:"<<getQueueSize()<<endl; 
    while(curr2!=NULL) 
    { 
     cout<<" |"<<curr2->value<<"|"; 
     curr2=curr2->prev; 
    } 
    cout<<endl; 
}// print the Double Linked List from back 

int main() 
{ 
    dlist *st ; 
    st= new dlist(); 
    st->insertBack(8); 
    st->printDListFront(); 
    st->insertBack(5); 
    st->printDListFront(); 
    st->insertBack(6); 
    st->printDListFront(); 
    st->insertFront(1) ; 
    st->printDListFront(); 
    st->insertFront(3) ; 
    st->printDListFront(); 
    st->insertBack(7); 
    st->printDListFront(); 
    st->removeFront(); 
    st->printDListFront(); 
    st->removeBack(); 
    st->printDListFront(); 
} 

Maintenant, comment puis-je obtenir le programme pour afficher mes informations voir ci-dessous ... (sortie) comme comment puis-je afficher une liste vide?

List created using an empty value of 0. 
Empty list: 
     Going forwards, I see channel 0 
     Going forwards, I see channel 0 
     Going forwards, I see channel 0 
     Current channel is 0 
     Going backwards, I see channel 0 
     Going backwards, I see channel 0 
     Going backwards, I see channel 0 
Single node: 
     Going forwards, I see channel 2 
     Going forwards, I see channel 2 
     Going forwards, I see channel 2 
     Current channel is 2 
     Going backwards, I see channel 2 
     Going backwards, I see channel 2 
     Going backwards, I see channel 2 
Multiple nodes: 
     Going forwards, I see channel 2 
     Going forwards, I see channel 3 
     Going forwards, I see channel 7 
     Going forwards, I see channel 9 
     Going forwards, I see channel 10 
     Going forwards, I see channel 44 
     Going forwards, I see channel 2 
     Going forwards, I see channel 3 
     Going forwards, I see channel 7 
     Going forwards, I see channel 9 
     Going forwards, I see channel 10 
     Going forwards, I see channel 44 
     Current channel is 44 
     Going backwards, I see channel 10 
     Going backwards, I see channel 9 
     Going backwards, I see channel 7 
     Going backwards, I see channel 3 
     Going backwards, I see channel 2 
     Going backwards, I see channel 44 
     Going backwards, I see channel 10 
     Going backwards, I see channel 9 
     Going backwards, I see channel 7 
     Going backwards, I see channel 3 
     Going backwards, I see channel 2 
     Going backwards, I see channel 44 
List de-allocated. 

Answer 1

Vous avez affaire à une liste doublement chaînée ici et de ce que je peux comprendre de votre question que vous souhaitez afficher un message approprié lorsque vous naviguez ou de créer des noeuds.

Pour ce faire, vous devez insérer les déclarations cout<< appropriées dans chaque fonction que vous appelez de la Main()