GATE 2023 CS – Question 47

Consider the C function foo and the binary tree shown.

typedef struct node {
  int val;
  struct node *left, *right;
} node;
int foo(node *p) {
  int retval;
  if (p == NULL)
    return 0;
  else {
    retval = p->val + foo(p->left) + foo(p->right);
    printf("%d ", retval);
    return retval;
  }
}

[Figure: binary tree with root 10; left child 5 with children 3 and 8; right child 11 with right child 13.] When foo is called with a pointer to the root node of the given binary tree, what will it print?