need help with my DSA assignment code | Together C & C++ | Page 1

umbral jewel Sep 30, 2025, 11:09 PM

#

using namespace std;

class Cart{
    public:
        int fruitPrice;
        Cart* next;

        Cart(int price){
            fruitPrice=price;
            next=NULL;
        }
};

class SinglyLinkedList{
    public:
    
        Cart* head;

        SinglyLinkedList(){
            head=NULL;
        }

        void add_item(int price){
            Cart* itemToAdd= new Cart(price);

            if (head==NULL){
                head=itemToAdd;
                itemToAdd->next=NULL;
            }

            else{
                Cart* temp=head;

                while(temp->next!=NULL){
                    temp=temp->next;
                }
                temp->next=itemToAdd;
                itemToAdd->next=NULL;
            }
        }

         
        void returnList(){
            
            if (head==NULL){
                cout<<"List is empty";}
                
            
            else{    
                Cart* temp=head;
            

                while (temp->next!=NULL){
                    cout<<temp->fruitPrice<<endl;
                    temp=temp->next;
                }
                cout<<temp->fruitPrice;
            }
        }

        void DivideEvenAndOdd(){
            if(head==NULL){
                cout<<"List is empty";
            }

            else{
                SinglyLinkedList newlist;
                Cart* temp;
                Cart* temp2=NULL;


                    while(this->head!=NULL && this->head->fruitPrice%2==0  ){

                        if (newlist.head==NULL){

                            newlist.head=this->head;
                            temp2=this->head;
                            this->head=this->head->next;
                            temp2->next=NULL;
                    }
                        else{
                            temp2->next=this->head;
                            this->head=this->head->next;
                            temp2=temp2->next;
                            temp2->next=NULL;
                        }
                    } 
                    
                    temp=head;

                    while (temp!=NULL && temp->next!=NULL){

                        if(temp->next->fruitPrice%2==0){

                            if(newlist.head==NULL){
                                newlist.head=temp2=temp->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                            else{
                                temp2->next=temp->next;
                                temp2=temp2->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                    
                    }
                        else{
                            temp=temp->next;
                        }

                    }
                    this->returnList();
                    cout<<endl<<endl;
                    newlist.returnList();

                }

                
                }


};
                    
int main(){

    SinglyLinkedList sll;
    sll.add_item(10);
    sll.add_item(15);
    sll.add_item(35);
    sll.add_item(16);
    sll.DivideEvenAndOdd();
}```

hallow dragonBOT Sep 30, 2025, 11:09 PM

#

When your question is answered use !solved to mark the question as resolved.

Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For tips on how to ask a good question use !howto ask.

umbral jewel Sep 30, 2025, 11:10 PM

#

I made this code for my assignment question, but there's some logical error in this code and I know where it lies
but I am unable to fix it despite trying multiple solutions
The logical error lies in this part of code

#

the error lies in this part:


                            newlist.head=this->head;
                            temp2=this->head;
                            this->head=this->head->next;
                            temp2->next=NULL;
                    }```

cedar tartan Sep 30, 2025, 11:11 PM

#

umbral jewel ```#include <iostream> using namespace std; class Cart{ public: int...

!code

hallow dragonBOT Sep 30, 2025, 11:11 PM

#

How to Format Code on Discord

Markup

```cpp
int main() {}
```

Result

int main() {}

mild prismBOT Sep 30, 2025, 11:11 PM

#

How to Format Code on Discord

Markup

```cpp
int main() {}
```

Result

int main() {}

umbral jewel Sep 30, 2025, 11:11 PM

#

for some reason, my this->head starts pointing towards NULL after first iteration of the first while loop inside DivideEvenandOdd() function

#

This is the question I am trying to solve

#


#include <iostream>
using namespace std;

class Cart{
    public:
        int fruitPrice;
        Cart* next;

        Cart(int price){
            fruitPrice=price;
            next=NULL;
        }
};

class SinglyLinkedList{
    public:
    
        Cart* head;

        SinglyLinkedList(){
            head=NULL;
        }

        void add_item(int price){
            Cart* itemToAdd= new Cart(price);

            if (head==NULL){
                head=itemToAdd;
                itemToAdd->next=NULL;
            }

            else{
                Cart* temp=head;

                while(temp->next!=NULL){
                    temp=temp->next;
                }
                temp->next=itemToAdd;
                itemToAdd->next=NULL;
            }
        }

         
        void returnList(){
            
            if (head==NULL){
                cout<<"List is empty";}
                
            
            else{    
                Cart* temp=head;
            

                while (temp->next!=NULL){
                    cout<<temp->fruitPrice<<endl;
                    temp=temp->next;
                }
                cout<<temp->fruitPrice;
            }
        }

        void DivideEvenAndOdd(){
            if(head==NULL){
                cout<<"List is empty";
            }

            else{
                SinglyLinkedList newlist;
                Cart* temp;
                Cart* temp2=NULL;


                    while(this->head!=NULL && this->head->fruitPrice%2==0  ){

                        if (newlist.head==NULL){

                            newlist.head=this->head;
                            temp2=this->head;
                            this->head=this->head->next;
                            temp2->next=NULL;
                    }
                        else{
                            temp2->next=this->head;
                            this->head=this->head->next;
                            temp2=temp2->next;
                            temp2->next=NULL;
                        }
                    } 
                    
                    temp=head;

                    while (temp!=NULL && temp->next!=NULL){

                        if(temp->next->fruitPrice%2==0){

                            if(newlist.head==NULL){
                                newlist.head=temp2=temp->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                            else{
                                temp2->next=temp->next;
                                temp2=temp2->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                    
                    }
                        else{
                            temp=temp->next;
                        }

                    }
                    this->returnList();
                    cout<<endl<<endl;
                    newlist.returnList();

                }

                
                }


};
                    
int main(){

    SinglyLinkedList sll;
    sll.add_item(10);
    sll.add_item(15);
    sll.add_item(35);
    sll.add_item(16);
    sll.DivideEvenAndOdd();
}```

#

here @cedar tartan

cedar tartan Sep 30, 2025, 11:15 PM

#

umbral jewel for some reason, my this->head starts pointing towards NULL after first iteratio...

have you stepped through your code in a debugger yet?

umbral jewel Sep 30, 2025, 11:16 PM

#

cedar tartan have you stepped through your code in a debugger yet?

yep

#

it just runs for one iteration and then gets out of loop

cedar tartan Sep 30, 2025, 11:18 PM

#

Look at what's happening during the execution though, where do things go wrong with the pointers

umbral jewel Sep 30, 2025, 11:19 PM

#

cedar tartan Look at what's happening during the execution though, where do things go wrong w...

ah ok, I think i found the logical error

#

it's not with the head pointer mis assignment, right?

#

it's the condition this->head->fruitPrice%2==0

umbral jewel Sep 30, 2025, 11:45 PM

#

@cedar tartanI fixed the code. Now there's one more error left that I need help with

#


#include <iostream>
using namespace std;

class Cart{
    public:
        int fruitPrice;
        Cart* next;

        Cart(int price){
            fruitPrice=price;
            next=NULL;
        }
};

class SinglyLinkedList{
    public:
    
        Cart* head;

        SinglyLinkedList(){
            head=NULL;
        }

        void add_item(int price){
            Cart* itemToAdd= new Cart(price);

            if (head==NULL){
                head=itemToAdd;
                itemToAdd->next=NULL;
            }

            else{
                Cart* temp=head;

                while(temp->next!=NULL){
                    temp=temp->next;
                }
                temp->next=itemToAdd;
                itemToAdd->next=NULL;
            }
        }

         
        void returnList(){
            
            if (head==NULL){
                cout<<"List is empty";}
                
            
            else{    
                Cart* temp=head;
            

                while (temp->next!=NULL){
                    cout<<temp->fruitPrice<<"=>";
                    temp=temp->next;
                }
                cout<<temp->fruitPrice;
            }
        }

        void DivideEvenAndOdd(){
            if(head==NULL){
                cout<<"List is empty";
            }

            else{
                SinglyLinkedList newlist;
                Cart* temp;
                Cart* temp2=NULL;


                    while(this->head!=NULL && this->head->fruitPrice%2==0  ){

                        if (newlist.head==NULL){

                            newlist.head=this->head;
                            temp2=this->head;
                            this->head=this->head->next;
                            temp2->next=NULL;
                    }
                        else{
                            temp2->next=this->head;
                            this->head=this->head->next;
                            temp2=temp2->next;
                            temp2->next=NULL;
                        }
                    } 
                    
                    temp=head;
                  

                    while (temp!=NULL && temp->next!=NULL){

                        if(temp->next->fruitPrice%2==0){

                            if(newlist.head==NULL){
                                newlist.head=temp2=temp->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                            else{
                                temp2->next=temp->next;
                                temp2=temp2->next;
                                temp2->next=NULL;
                                temp=temp->next->next;
                                
                        }
                    
                    }
                        else{
                            temp=temp->next;
                        }

                    }
                    this->returnList();
                    cout<<endl<<endl;
                    newlist.returnList();

                }
                
                }


};
                    
int main(){

    SinglyLinkedList sll;
    sll.add_item(10);
    sll.add_item(15);
    sll.add_item(35);
    sll.add_item(16);
    sll.add_item(24);
    sll.add_item(367);

    sll.DivideEvenAndOdd();
}```

#

this is the fixed code

#


10=>16```

#

This is the output I'm getting

#

Error lies somewhere in this part of code:

#


temp=head;
                  

                    while (temp!=NULL && temp->next!=NULL){

                        if(temp->next->fruitPrice%2==0){

                            if(newlist.head==NULL){
                                newlist.head=temp2=temp->next;
                                temp2->next=NULL;
                                temp->next=temp->next->next;
                        }
                            else{
                                temp2->next=temp->next;
                                temp2=temp2->next;
                                temp2->next=NULL;
                                temp=temp->next->next;
                                
                        }
                    
                    }
                        else{
                            temp=temp->next;
                        }

                    }
                    this->returnList();
                    cout<<endl<<endl;
                    newlist.returnList();

                }
                
                }```

#need help with my DSA assignment code