Runtime error while recursively calling a function with a double pointer as its default argument in c++

What I am trying to do:

I am trying to delete a node in a binary search tree. But before deleting the node we first have to search if the node exists and that I am checking in my search function which returns the address of the node where the match is found.

What is the problem:

After execution, the program throws an exception: Process returned -1073741819 (0xC0000005) And I believe the problem is with the statement (*parent) = root;But I don't know why it does so. And how to fix it.

My code:

Struct Defined As:

struct tree{
    int data;
    struct tree *left, *right;
};

Search function:

tree * search(tree *root, int value, tree **parent = NULL){

    tree * target = NULL;
    if (!root) return root;
    if (root->data == value) return root;
    if (value < root->data){
        // This returns the matched node
        target = search(root->left, value);
        // and this stores the parent of the matched node
        if (root->left->data == value)
            (*parent) = root;
    } else {
        target = search(root->right, value);
        if (root->right->data == value)
            (*parent) = root;
    }
    return target;
}

Delete function:

void del(tree *root, int value){
    tree * parent = NULL;
    if (!root) return;
    tree *target = search(root, value, &parent);
    // Deletion logic goes here
}

The simple reason is that *parent=... is an assignment. That requires that parent is a valid (non-null) pointer. Yet you use nullptr as the default value of parent.

You'll need to fix the design of this function. This is not the only flaw.