What kind of error in Binary search code? - c

Question

I am implementing the binary search tree with some operations ( new node, search, insert and display).
It results in following warning.
binarytree.c:70: warning: assignment makes pointer from integer without a cast
binarytree.c:72: warning: assignment makes pointer from integer without a cast
binarytree.c:73: warning: return makes integer from pointer without a cast
binarytree.c: At top level:
binarytree.c:78: warning: conflicting types for ‘printInoder’
binarytree.c:47: warning: previous implicit declaration of ‘printInoder’ was here
binarytree.c: In function ‘NewNode’:
binarytree.c:122: warning: return makes pointer from integer without a cast
Undefined symbols for architecture x86_64:
"_newNode", referenced from:
_main in cckg2mll.o
_insert in cckg2mll.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
You will see my source code here below but I wish to hear your suggestions. I fully understand the Binary trees functions but I think it is not related to any algorithm but it is a programming problem.
Source Code
It is really long code but I cannot reduce it for your guys.
#include <stdlib.h>
#include <stdio.h>
#define false 0
#define true 1
struct Node
{
int data;
struct Node *left, *right;
}*node,*root;
int main(void)
{
root = (struct Node *)malloc(sizeof(struct Node));
int option = 1;
int choice,value,target,newvalue;
while(option)
{
printf("Enter your choice \n");
scanf("%d\n",&choice);
switch(choice)
{
case 1:
printf("Enter the a new value\n");
insert(root,value);
scanf("%d\n",&value);
break;
case 2:
printf("Enter the traget \n");
scanf("%d\n",&target);
lookup(root,target);
break;
case 3:
printf("Enter the new node \n");
scanf("%d\n",&newvalue);
newNode();
break;
case 4:
printInoder();
break;
}
printf("Enter 0 or 1\n");
scanf("%d\n",&option);
}
}
int insert(struct Node *node ,int data)
{
// 1. If the tree is empty, return a new, single node
node = (struct Node *)malloc(sizeof(struct Node));
if (node == NULL)
{
return(newNode(data));
}
else
{
// 2. Otherwise, recur down the tree
if (data <= node->data)
node->left = insert(node->left, data);
else
node->right = insert(node->right, data);
return(node); // return the (unchanged) node pointer
}
}
void printInoder()
{
root = (struct Node *)malloc(sizeof(struct Node));
if (root != NULL)
{
printInoder(root->left);
printf("%d ",root->data);
printInoder (root->right);
}
}
int lookup(struct Node *node, int target)
{
node = (struct Node *)malloc(sizeof(struct Node));
// 1. Base case == empty tree
// in that case, the target is not found so return false
if (node == NULL)
{
return(false);
}
else
{
// 2. see if found here
if (target == node->data) return(true);
else
{
// 3. otherwise recur down the correct subtree
if (target < node->data)
return(lookup(node->left, target));
else return(lookup(node->right, target));
}
}
}
struct Node *NewNode(int x)
{
node =(struct Node *)malloc(sizeof(struct Node)); // "new" is like "malloc"
node->data = x;
node->left = NULL;
node->right = NULL;
return(x);
}

Answer 1

So, the biggest issue is that you ignore data types. insert function returns int but whenever you assign its return value or even return something inside this function, the variables you use are pointers instead - so change return type of insert to struct Node *node.
Also, in case 4 part, you use function printInoder which is declared and defined after calling it (below main function) so that is why it warns you that you should at least declare this function before main.
Finally, inside insert function, you call newNode but this function is called NewNode and it is also declared and defined below main.

Answer 2

You called the following function using newNode not NewNode. Also, move the * off of the NewNode part.
struct Node *NewNode(int x)
{
node =(struct Node *)malloc(sizeof(struct Node)); // "new" is like "malloc"
node->data = x;
node->left = NULL;
node->right = NULL;
return(x);
}
Your insert function returns a node pointer but is declared with an int return type.
Also, you need to declare functions above where they are called the first time. add a declaration statement to the top of the page for your functions to work.
return_type function_name(params);
Finally, rename your function to printInOrder() instead of printInoder()

Answer 3

Your code has many errors.
I've edited it a bit:
#include <stdlib.h>
#include <stdio.h>
#define false 0
#define true 1
struct Node
{
int data;
struct Node *left, *right;
};
void insert(struct Node **node, int data);
int lookup(struct Node *node, int target);
void printInoder(struct Node *root);
struct Node *NewNode(int x);
int main(void)
{
struct Node *root = NULL;
int option = 1;
int choice, value, target;
while (option)
{
choice = value = target = 0;
printf("Enter your choice \n");
scanf("%d", &choice);
switch (choice)
{
case 1:
printf("Enter the a new value\n");
scanf("%d", &value);
insert(&root, value);
break;
case 2:
printf("Enter the traget \n");
scanf("%d", &target);
printf("%d\n", lookup(root, target));
break;
case 3:
printf("Printing\n");
printInoder(root);
printf("\n");
break;
}
printf("Enter 0 or 1\n");
scanf("%d", &option);
}
return 0;
}
void insert(struct Node **root, int data)
{
// 1. If the tree is empty, return a new, single node
struct Node *node = NewNode(data);
if (*root == NULL)
{
*root = node;
return;
}
// 2. Otherwise, recur down the tree
if (data <= (*root)->data)
insert(&(*root)->left, data);
else
insert(&(*root)->right, data);
}
void printInoder(struct Node *root)
{
if (root == NULL) return;
printInoder(root->left);
printf("%d ", root->data);
printInoder(root->right);
}
int lookup(struct Node *root, int target)
{
// 1. Base case == empty tree
// in that case, the target is not found so return false
if (root == NULL)
{
return(false);
}
// 2. see if found here
if (target == root->data) return(true);
// 3. otherwise recur down the correct subtree
if (target < root->data)
return(lookup(root->left, target));
else return(lookup(root->right, target));
}
struct Node *NewNode(int x)
{
struct Node *node= malloc(sizeof *node);
node->data = x;
node->left = NULL;
node->right = NULL;
return node;
}
Try it, and take a look at the changes in the code.