[C language] implementation of binary tree and three Traversals

Implement the binary tree and traverse it

 The concept of binary tree will not be explained , Use the secondary pointer to operate , It's more convenient .
 The node value must be greater than 0, Otherwise, the node is set to NULL.

 Environmental Science ：Ubuntu18.04 GCC Compile and use 

Code：

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

// node 
struct BinTreeNode
{
    
	int value;
	struct BinTreeNode *left;
	struct BinTreeNode *right;
};

// Create trees 
int CreatBinTree(struct BinTreeNode **root)
{
    
	int val;
	scanf("%d", &val);

	if (val <= 0)
	{
    
		*root = NULL;
		return 0;
	}

	*root = (struct BinTreeNode*)malloc(sizeof(struct BinTreeNode));

	if (!(*root))
	{
    
		perror("Failed to creat:");
		return -1;
	}

	else
	{
    
		(*root)->value = val;
		printf("%d Left sibling:", val);
		CreatBinTree(&((*root)->left));
		printf("%d Right sibling:", val);
		CreatBinTree(&((*root)->right));
	}
	return 0;
}

// The former sequence traversal 
int PreorderTraversal(struct BinTreeNode *root)
{
    
	if (!root)
		return -1;
	
	printf("%d,", root->value);
	PreorderTraversal(root->left);
	PreorderTraversal(root->right);
	return 0;
}

// After the sequence traversal 
int PostorderTraversal(struct BinTreeNode *root)
{
    
	if (!root)
		return -1;
	
	PostorderTraversal(root->left);
	PostorderTraversal(root->right);
	printf("%d,", root->value);
	return 0;
}

// In the sequence traversal 
int InorderTraversal(struct BinTreeNode *root)
{
    
	if (!root)
		return -1;
	
	InorderTraversal(root->left);
	printf("%d,", root->value);
	InorderTraversal(root->right);
	return 0;
}

int main(int argc, char const *argv[])
{
    
	struct BinTreeNode *root = (struct BinTreeNode*)malloc(sizeof(struct BinTreeNode*));

	CreatBinTree(&root);

	printf("Preorder Traversal:\n");
	PreorderTraversal(root);
	printf("\n");

	printf("Inorder Traversal:\n");
	InorderTraversal(root);
	printf("\n");

	printf("Postorder Traversal:\n");
	PostorderTraversal(root);
	printf("\n");
	return 0;
}

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