CODEWITHSUNDEEP
c++crashlinked-listnodes
Franky
Franky

Reputation: 35

Delete_At Function for Linked List crashing the program

I created a Linked List class ,everything works just fine but when i run Delete_At Function it get crashed ! , no syntax errors given , it's logical,i really don't know what i am missing

here is the code :

#include <iostream>
using namespace std;



struct node{

int info;

node *link;

};


class Linked_List{


private :

int count;
node *first;
node *last;
node *current;

public:


Linked_List() {

count=0;
first=NULL;
last=NULL;
}



void Initialize_List(){

cout<<"Enter Number OF Nodes"<<endl;
cin>>count;

first=last=current=new node;

for(int i =0;i<count;i++){
cout<<"Enter New Node Info :"<<endl;
cin>>current->info;
last->link=current;
last=current;
current=new node;}
last->link=NULL;
}


void Insert_At (int loc,int element){


for (current=first;current!=NULL;current=current->link){
if (current->info==loc){

node *newnode= new node;
newnode->info=element;

newnode->link=current->link;
current->link=newnode;
count++;}
}
if(current==last){
node *newnode= new node;
newnode->info=element;

last->link=newnode;
last=newnode;
newnode->link=NULL;}
}


void Delete_At(int loc){
bool found;

node *p=new node;
if(first ==NULL)
cout<<"can't delete from empty list"<<endl;


else {
found = false ;
current=first;
p=first->link;

while (p!=NULL){

if(p->info!=loc){

current=p;
p=p->link;}

else found = true;}

if (found) {
current->link=p->link;
count--;
delete p;} }}
};

void main (){


Linked_List obj;

obj.Initialize_List();

obj.print();

obj.Insert_At(3,10); cout<<"item inserrted"<<endl;

obj.print();

obj.Delete_At(3);  cout<<"item deleted"<<endl;   //lets say i have  number 3 in my 
list.

obj.print();

}

Upvotes: 0

Views: 51

Answers (1)

The Dark
The Dark

Reputation: 8514

Your while loop loops until p is NULL, even if the node is found. Then you immediately dereference p in the current->link=p->link line, when p is guaranteed to be NULL.

You need to break out of the while loop when you have found the right node. Putting && !found into the while clause would do it.

Note that this is made harder to spot by the lack of indentation, I don't know if that is due to the cut-and-paste or if it is how you wrote it.

Upvotes: 1

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