What's the error?

hooshdar3 (257)
Hello. I am just trying to delete a list element, But I get a run-time error(don't know the swource):

Here is what I did:


#include <iostream>
using namespace std;

main(){

struct Node{
int data;
Node *next;
}*ptr;

Node *head;

ptr = new Node;

ptr->data = 1;
head = ptr;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 2;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 3;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 4;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 5;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 6;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 7;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 8;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 9;
ptr->next = new Node;
ptr = ptr->next;
ptr->data = 10;

ptr->next = NULL;



for(Node *a = head;a;a = a->next)
{
cout << a->data;
if( a->next)
cout << "->";
if( a->next->data == '8' )
{//deletes node #9
cout << "here";
// a->next = a->next->next;
// a->next->next = NULL;
}

}

cin.get();


return 0;
}

What's wrong with my code?
ciphermagi (807)
First thing that's wrong with it is that it's not indented or in code brackets. I fixed that below:

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#include <iostream>
using namespace std;

main(){

    struct Node{
        int data;
        Node *next;
    }*ptr;

    Node *head;

    ptr = new Node;

    ptr->data = 1;
    head = ptr;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 2;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 3;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 4;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 5;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 6;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 7;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 8;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 9;
    ptr->next = new Node;
    ptr = ptr->next;
    ptr->data = 10;

    ptr->next = NULL;



    for(Node *a = head;a;a = a->next)
    {
        cout << a->data;
        if( a->next)
        cout << "->";
        if( a->next->data == '8' )
        {//deletes node #9
            cout << "here";
            // a->next = a->next->next;
            // a->next->next = NULL;
        }

    }

    cin.get();
    return 0;
}


You can get much the same functionality by looking up vectors, lists, deques and iterators, but it looks like the for loop won't activate because you've set a termination condition that's too ambiguous.
hooshdar3 (257)
OK thank you.I corrected the fault, but now the problem is that it doesn't delete a node!

Here is my new code

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#include <iostream>
using namespace std;

main(){
   
   struct Node{
          int data;
          Node *next;
          }*ptr;
          
   Node *head;
       
       ptr = new Node;  
       
       ptr->data = 1;
       head = ptr;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 2;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 3;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 4;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 5;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 6;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 7;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 8;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 9;
       ptr->next = new Node;
       ptr = ptr->next;
       ptr->data = 10;
       
       ptr->next = NULL;
       
       
       
       for(Node *a = head;a->next != NULL;a = a->next)
       {
         
          if(  a->next->data == '7' )
          {//deletes node #9
            cout << "here";
               a->next = a->next->next;
               delete a->next->next ;
          }
                 
       }
          
          for(Node *a = head;a->next != NULL;a = a->next)
       {
                   cout << a->data;
          if( a->next)
             cout << "->";  
       }
       cin.get();
                 
   
   return 0;
}
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