isLeafandBranch.swift

class DecimalTreeNode {
    ...
    func isLeaf() -> Bool {
        // Check if the current node is a leaf or not
        // Count the number of nil values in self.next
        for item in self.next {
            if item != nil {  // There is a child of the node
             return false
            }
        }
        // The node has no children
        return true
    }
    
    func isBranch() -> Bool{
        // Check if the current node is a branch or not
        return !self.isLeaf()
    }
}