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This is a linked list code, I just want to delete a specific number from the list e.g: a list contains(10,20,18,17,15) lets say that I want to delete 17, How to search for the address of this node and then delete it? my code always delete the head

What I have tried:

C++
class node {
    public:
        int data;
        node* next;
    };
    
    class Linkedlist {
    public:
        Linkedlist() {
            head = NULL;
        }
        void AddNode(int val);
        void Display();
bool Remove(int k);
	node *getPTRto(int it);
  
    private:
        node* head;
    };
    
   node *Linkedlist::getPTRto(int it)
{
    node*ptr= head;
    while (ptr != NULL)
    {
        if (ptr->data == it)
        {
            return ptr;
        }
        ptr = ptr->next;
    }
    return NULL;
}
bool Linkedlist::Remove(int k)
{
    node* ptr = getPTRto(k);
    if (!ptr) return false;
    ptr = head;
    node* temp = head;
    head = head->next;
    delete temp;
    return true;
}
Posted
Updated 7-Nov-20 7:39am
v3

1 solution

C++
bool Linkedlist::Remove(int k)
{
    node* ptr = getPTRto(k); // Here you get the node in linked list
    if (!ptr) return false;
    ptr = head;              // here you kill the information
                             // and you don't reuse ptr after that
    node* temp = head;
    head = head->next;
    delete temp;
    return true;
}

Quote:
ow to search for the address of this node and then delete it? my code always delete the head

Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your code is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]

1.11 — Debugging your program (stepping and breakpoints) | Learn C++[^]

The debugger is here to only show you what your code is doing and your task is to compare with what it should do.

Advice: write down a sample linked list and write the changes needed to remove a value from the list and alsi try to remove first value, see changes in this case. Your code must replicate those changes.
Position Value Next
head           3

3        10    4
4        20    5
5        18    6
6        17    7
7        15    0

Add 3 columns to reflect changes when remove first value, last value, and value in middle. Pay attention to where value change ans where ir come from.
   
v3
Comments
KarstenK 7-Nov-20 13:41pm
   
plz check your Remove(). I think it isnt correct :-O
Patrice T 7-Nov-20 13:44pm
   
It is not mine, just commented OP's code.

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