Question

Having some problems with my given code. Thou it works accordingly, im required to implement the “transverse” & “transverseR” functions.

Also i have trouble understanding what the given function pointers are for:
Function pointers => void (*visit)(link)

void traverse (link ls, void (*visit)(link)) {
  if (ls == NULL) {
    return;
  }
  (*visit) (ls);
  traverse (ls->next, visit);
  return;
}

void traverseR (link ls, void (*visit)(link)) {
  if (ls == NULL) {
    return;
  }
  traverseR (ls->next, visit);
  (*visit)(ls);
  return;
}


void square (link l) {
  // link tmp = NULL;
  int container = l->item;
  container = SQUARE(container);

  l->item = container;

}

void squareAll (link ls){

  link curr = ls;  
  while (curr != NULL){
    square(curr);
    curr = curr->next;
  }

  ls = curr;
}

Answer 1

These function pointers allows you to perform some custom actions using a function of your own on each list item as a list is being traversed. For example, you might write a function that decreases each node’s data:

void decrease_item(link node)
{
  --node->item;
}

The when you can call traverse(list_head, decrease_item) to decrease a value of every item in a list. You can create a function for printing each element’s item and so on.

Btw, in your code above you can rewrite squareAll function in a more elegant manner:

void squareAll (link ls){
   traverse(ls, square);
}