GATE 2014 CS (CS3) – Question 51

An arbitrary tree uses leftMostChild–rightSibling representation. When its root is passed to DoSomething, what does the returned value count?

typedef struct treeNode* treeptr;
struct treeNode {
treeptr leftMostChild, rightSibling;
};
int DoSomething(treeptr tree) {
int value = 0;
if (tree != NULL) {
if (tree->leftMostChild == NULL) value = 1;
else value = DoSomething(tree->leftMostChild);
value = value + DoSomething(tree->rightSibling);
}
return value;
}