Thread: binary trees..compiler error?

Im trying to write a binary tree library and this is the only function giving me trouble(so far..)


when i compile, it says:

bintree.c:32: error: void value not ignored as it ought to be
bintree.c:34: error: void value not ignored as it ought to be

Code:

typedef struct _bnode{
    char *name;
    struct _node family_node;
    struct _bnode *left;
    struct _bnode *right;
} BNODE;


void tree_insert(char *key, void *value, void *tree){
    BNODE *root = (BNODE *)tree;
    if(root == 0){
        root = (BNODE *)malloc(sizeof(BNODE));
        root->name = strdup(key);
        root->left = NULL;
        root->right = NULL;
    }else{
        if(strcmp(key, root->name) == -1){
            root->left = tree_insert(key, value, root->left); <-- line 32
        }else if(strcmp(key, root->name) == 1){
            root->right = tree_insert(key, value, root->right); <--line 34
        }else if(strcmp(key, root->name) == 0){
            //do something

        }
    }
}

will someone please tell me what im doing wrong?

thankyou

Code:

typedef struct _bnode{
    char *name;
    struct _node family_node;
    struct _bnode *left;
    struct _bnode *right;
} BNODE;


void tree_insert(char *key, void *value, void *tree){
    BNODE *root = (BNODE *)tree;
    if(root == 0){
        root = (BNODE *)malloc(sizeof(BNODE));
        root->name = strdup(key);
        root->left = NULL;
        root->right = NULL;
    }else{
        if(strcmp(key, root->name) == -1){
            root->left = tree_insert(key, value, root->left); <-- line 32
        }else if(strcmp(key, root->name) == 1){
            root->right = tree_insert(key, value, root->right); <--line 34
        }else if(strcmp(key, root->name) == 0){
            //do something

        }
    }
}

You are trying to make something equal to something that has no return. I believe what you want to do is have this function return void * instead.

Originally Posted by master5001

Code:

typedef struct _bnode{
    char *name;
    struct _node family_node;
    struct _bnode *left;
    struct _bnode *right;
} BNODE;


void tree_insert(char *key, void *value, void *tree){
    BNODE *root = (BNODE *)tree;
    if(root == 0){
        root = (BNODE *)malloc(sizeof(BNODE));
        root->name = strdup(key);
        root->left = NULL;
        root->right = NULL;
    }else{
        if(strcmp(key, root->name) == -1){
            root->left = tree_insert(key, value, root->left); <-- line 32
        }else if(strcmp(key, root->name) == 1){
            root->right = tree_insert(key, value, root->right); <--line 34
        }else if(strcmp(key, root->name) == 0){
            //do something

        }
    }
}

You are trying to make something equal to something that has no return. I believe what you want to do is have this function return void * instead.

so should i return a bnode at the //do somthing? I had a bnode returning there.. and it gave me an error.. soo... where should i return the bnode?

Originally Posted by master5001

Code:

typedef struct _bnode{
    char *name;
    struct _node family_node;
    struct _bnode *left;
    struct _bnode *right;
} BNODE;
 
 
BNODE *tree_insert(char *key, void *value, void *tree){
    BNODE *root = (BNODE *)tree;
    if(root == 0){
       root = (BNODE *)malloc(sizeof(BNODE));
       if(root != NULL)
       {
           root->name = strdup(key);
           root->left = NULL;
           root->right = NULL;
       }
    }else{
        if(strcmp(key, root->name) == -1){
            root->left = tree_insert(key, value, root->left); <-- line 32
        }else if(strcmp(key, root->name) == 1){
            root->right = tree_insert(key, value, root->right); <--line 34
        }else if(strcmp(key, root->name) == 0){
            //do something
 
        }
    }
 
    /* Here */
    return root;
}

yay thankyou so much!

Yeah no problem. The reason for the blue code is because you can at least cope with malloc() returning nothing now.