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/*
C: The Complete Reference, 4th Ed. (Paperback)
by Herbert Schildt
ISBN: 0072121246
Publisher: McGraw-Hill Osborne Media; 4 edition (April 26, 2000)
*/
/* This program displays a binary tree. */
#include <stdlib.h>
#include <stdio.h>
struct tree {
char info;
struct tree *left;
struct tree *right;
};
struct tree *root; /* first node in tree */
struct tree *stree(struct tree *root,
struct tree *r, char info);
void print_tree(struct tree *root, int l);
int main(void)
{
char s[80];
root = NULL; /* initialize the root */
do {
printf("Enter a letter: ");
gets(s);
root = stree(root, root, *s);
} while(*s);
print_tree(root, 0);
return 0;
}
struct tree *stree(
struct tree *root,
struct tree *r,
char info)
{
if(!r) {
r = (struct tree *) malloc(sizeof(struct tree));
if(!r) {
printf("Out of Memory\n");
exit(0);
}
r->left = NULL;
r->right = NULL;
r->info = info;
if(!root) return r; /* first entry */
if(info < root->info) root->left = r;
else root->right = r;
return r;
}
if(info < r->info)
stree(r, r->left, info);
else
stree(r, r->right, info);
return root;
}
void print_tree(struct tree *r, int l)
{
int i;
if(!r) return;
print_tree(r->right, l+1);
for(i=0; i<l; ++i) printf(" ");
printf("%c\n", r->info);
print_tree(r->left, l+1);
}
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