error: request for member 'data' in something not a structure or union|

Question

I'm trying to practice binary trees.

I created a struct for node, allocated it for the root and also allocated space for the left son.

I built a function that returns the size of the tree but it seems there is an error while trying to initialize the left son's variables.

The main function:

int main()
{
    node* root = (node*) malloc(sizeof(node));//allocate space for root
    root->data = 7;
    root->left = (node*) malloc(sizeof(node));//allocate space for left son of root
    root->right = NULL;

    root->left.data = 8;//ERROR HERE!
    root->left.left = NULL;//ERROR HERE!
    root->left.right = NULL;//ERROR HERE!

    printf("size of tree: %d\n", sizeOfTree(root));

    return 0;
}

The node struct:

typedef struct
{
    int data;
    struct node* left;
    struct node* right;
} node;

The errors I get:

Error: request for member 'data' in something not a structure or union|
Error: request for member 'left' in something not a structure or union|
Error: request for member 'right' in something not a structure or union|

What am I doing wrong?

Answer 1

You got error there because you try to access that pointer with . instead of ->. Also typedef struct should be typedef struct node.

Try this:

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

typedef struct node{
    int data;
    struct node* left;
    struct node* right;
}node;


int main(void){
    node* root = malloc(sizeof(node));//allocate space for root
    root->data = 7;
    root->left = malloc(sizeof(node));//allocate space for left son of root
    root->right = NULL;

    root->left->data = 8;//ERROR HERE!
    root->left->left = NULL;//ERROR HERE!
    root->left->right = NULL;//ERROR HERE!


    printf("size of tree: %d\n", sizeOfTree(root));
    return 0;
}

Don't cast malloc because return of malloc is void*.