Write a recursive function in  that checks whether a given binary tree is a full binary tree. The function will return true if the tree is full tree, and otherwise it will return false. Assume that a binary tree node class has already been declared as follows.

class TreeNode {

int value;

TreeNode *left;

TreeNode *right;

TreeNode(int  ) {

value =

left = NULL;

right = NULL;

};

write the function that performs the given task, do not write a main function.