Searching for a string in BST fails - c

Question

I am searching a string in a BST. If I found the string, I just return it. If not found, I print 3 suggestions:
the last traversed node before declaring that the node is not found
the inorder successsor
the inorder predecessor
My code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
void line() {
printf("\n-------------------------\n");
}
typedef struct node node;
struct node {
node* left, *right;
char *key;
};
node *newnode(char* key) {
node *n = malloc(sizeof(node));
n->key = malloc(strlen(key) + 1);
strcpy(n->key, key);
n->right = n->left = NULL;
return n;
}
node *insirtNode(node *root, char *key) {
if (!root) return newnode(key);
if (strcmp(key, root->key) < 0) {
root->left = insirtNode(root->left, key);
} else if (strcmp(key, root->key) > 0) {
root->right = insirtNode(root->right, key);
}
return root;
}
node* search(node *root, char *key, node **pred, node **succ, node **last) {
if (root) {
//printf("%s:%s=%d.\n",root->key,key,strcasecmp(key,root->key));
if (strcasecmp(key, root->key) == 0) {
printf("%s - is correct", root->key);
line();
return root;
}
if (strcasecmp(key, root->key) < 0) {
if (!root->left) {
*last = root;
}
*succ = root;
return search(root->left, key, pred, succ, last);
} else {
if (!root->right) {
*last = root;
}
*pred = root;
return search(root->right, key, pred, succ, last);
}
} else return NULL;
}
int main() {
char input[60];
printf("enter a word:\n");
gets(input);
line();
node *pred = NULL, *succ = NULL, *temp = NULL, *last = NULL;
node *root = NULL;
root = insirtNode(root, "anas");
root = insirtNode(root, "anad");
root = insirtNode(root, "anay");
root = insirtNode(root, "anaz");
temp = search(root, input, &pred, &succ, &last);
if (!temp) {
printf("%s incorrect, suggestions: %s %s %s", input, succ->key, pred->key, last->key);
}
printf("\n");
return 0;
}
The functions sometimes work when the string
exist in the BST. If not, it returns garbage without printing anything.

Answer 1

There are these issues:
in the main function where succ->key, pred->key and last->key are accessed when any of these pointers could still be NULL.
Not a problem, but last is likely to be equal to either succ or pred, so probably you want to avoid printing the same key twice.
Suggested correction:
if (temp == NULL) {
printf("%s incorrect, suggestion(s):", input);
if (pred != NULL) printf(" %s", pred->key);
if (succ != NULL) printf(" %s", succ->key);
if (last != NULL && last != pred && last != succ) printf(" %s", last->key);
}
The call to malloc assumes that a char is a byte. This is wrong. So multiply the number of characters by sizeof(char):
n->key = malloc((strlen(key) + 1) * sizeof(char));