binary tree visualization

btree-latex.c

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

typedef struct _btree {
	int value;
	
	struct _btree *left;
	struct _btree *right;
} btree;

btree *create_node(int value) {
	btree *node;
	
	node = (btree *)malloc(sizeof(btree));
	if (node == NULL) { exit(1); }
	
	node->value = value;
	node->left = NULL;
	node->right = NULL;
	
	return node;
}

int node_cmp(int a, int b) {
	if (a > b) {
		return -1;	
	} else if (a < b) {
		return 1;
	}
	
	return 0;
}

void add_node(btree *root, btree *node) {
	if (node_cmp(node->value, root->value) < 0) 
	{
		//new value is greater
		if (root->right == NULL) {
			root->right = node;
		} else {
			add_node(root->right, node);
		}
	} 
	else if (node_cmp(node->value, root->value) > 0) 
	{
		//new value is smaller
		if (root->left == NULL) {
			root->left = node;
		} else {
			add_node(root->left, node);
		}
	}
	//do nothing if equal node found
}

void print_latex_qtree(btree *root) {
	if (root == NULL) {
		printf("{ } ");
	} else {
		printf("[.%d ", root->value);
		print_latex_qtree(root->left);
		print_latex_qtree(root->right);
		printf("] ");
	}
}

void delete(btree *root) {
	if (root != NULL) {
		delete(root->left);
		delete(root->right);
		free(root);
	}
}

/*
 * Required packages (ubunut):
 * -latex-beamer (pdflatex)
 * -texlive-humanities (qtree)
 * 
 * USAGE:
 * $ ./btree-latex > btree.tex
 * $ pdflatex btree.tex
 */
int main() {
	btree *simple=NULL;
	int items[] = {1,5,6,3,12,8,9,10,4,2,13,0,11,7,15,14,16}, i;

	simple = create_node(items[0]);
	for (i = 1; i < sizeof(items)/sizeof(items[0]); i++) {
		add_node(simple, create_node(items[i]));
	}
	
	printf("\\documentclass{article}\n\\usepackage[english]{babel}\n\\usepackage{qtree}\n\\begin{document}\n\\def\\qtreepadding{16pt}\n\\Tree ");
	print_latex_qtree(simple);
	printf("\n\\end{document}");
	
	delete(simple);
	

    return 0;
}