CODEWITHSUNDEEP
c++recursionlinked-listnodes
Cladius
Cladius

Reputation: 1

Compiler error recursion linked list

int insert(node* head) {
    if (head == NULL) {
        node* temp = new node;
        if (head == NULL) {
            cout << "Error";
            return 0;
        }
        temp->data = 20;
        temp->next = NULL;
    } else {
        temp->next = insert(temp->next);
    }
    return (temp);
}

I am trying to add node recursively but I got the error temp was not declared. I do not understand why I am getting this error. When I always define temp like this node* temp = new node; but now I got an error.

Upvotes: 0

Views: 46

Answers (2)

Shriraj
Shriraj

Reputation: 56

There seems to be multiple issues with your code:

int insert(node* head) { if (head == NULL) { node* temp = new node; // Newly created node will not be used at all if (head == NULL) { // as head is NULL it will return 0 cout << "Error"; return 0; } temp->data = 20; // Code unreachable temp->next = NULL; } else { temp->next = insert(temp->next); // Here you will again get an error for temp not declared } return (temp); }

Upvotes: 0

Jonathan Potter
Jonathan Potter

Reputation: 37202

Local variables are only visible inside the scope they're declared in, and you're declaring temp inside your first if statement. You need to move the definition outside the if clause:

int insert(node* head)
{
     node* temp=new node; // <- move to here
     if(head==NULL)
     {
          ...
     }
     else
     {
          ...
     }
     return temp;
}

Upvotes: 1

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