Jul 20

C Code Build a Binary Tree. 

#include <iostream>
#include <string.h>
#include <stdlib.h>

#pragma warning(disable : 4996)

#define MaxWordSize 100

// Declare a structure that holds data in a node
typedef struct {
	char word[MaxWordSize + 1];
} NodeData;

typedef struct treeNode {
	NodeData data;
	struct treeNode* left, * right;
} TreeNode, *TreeNodePtr;

typedef struct {
	TreeNodePtr root;
} BinaryTree;

TreeNodePtr buildTree(FILE *in) {

	char str[MaxWordSize + 1];
	
	//read one word from the file
	fscanf_s (in, "%s", str);

	//if we see @ then return null (end of current recursion)
	if (strcmp (str, "@") == 0) return NULL;

	//allocate space for a TreeNode
	TreeNodePtr p = (TreeNodePtr) malloc (sizeof(TreeNode));

	// copy the data to the tree node
	strcpy_s (p->data.word, str);

	// build the left sub tree using recursion
	p->left = buildTree(in);

	// build the right sub tree using recursion
	p->right = buildTree(in);

	return p;

} //end buildTree


// traverse the tree in in-order basis
// print the treee content in in-order basis
void inOrder(TreeNodePtr node) {	
	//printf("%s ", node->data.word);
	if (node != NULL) {
		inOrder(node->left);
		printf("%s ", node->data.word);
		inOrder(node->right);
	}
} //end inOrder


// main method
int main(){

	// declare a binary tree
	BinaryTree bt;

	//open the file where tree data are kept
	FILE *in = fopen("btree.in", "r");
	
	// build the tree
	bt.root = buildTree(in);

	inOrder(bt.root);

}