Conversion of objects attributes to and from pointers as function argument











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My function in c contains objects node, with two attributes Key* a pointer to a key object and int data. The signature of a method is key_comp(key, key), which requires two keys, however the node object contains a pointer to a key. I have tried using node->key and (Node).key however neither work as arguments for this method, how would you go about converting the key pointer to a key for use in a method?



typedef struct 
{
Node tree_nodes;
unsigned char *is_free;
int size;
} BStree_struct;

typedef BStree_struct BStree;

void insert_helper(int i, BStree bst, Node node){
if (i>= (*bst).size){
printf("Out of the range of the tree. n");
return;
}
if ((*bst).is_free[i]==1){
(*bst).tree_nodes[i] = node;
(*bst).is_free[i] = 0;
}else if (key_comp(bst->tree_nodes[i].key, node.key) >0){
insert_helper(2*i,bst,node);
}else if (key_comp(bst->tree_nodes[i].key, node.key) <0){
insert_helper(2*i+1, bst, node);
}
}

typedef struct {char *name; int id;} Key;
typedef struct {Key *key; int data;} Node;
Key *key_construct(char *in_name, int in_id);
int key_comp(Key key1, Key key2);
void print_key(Key *key);
void print_node(Node node);

typedef struct {Node *tree_nodes; unsigned char *is_free;
int size;} BStree_struct;
typedef BStree_struct* BStree;
BStree bstree_ini(int size);
void bstree_insert(BStree bst, Key *key, int data);
void bstree_traversal(BStree bst);
void bstree_free(BStree bst)









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  • 1




    Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
    – Kingsley
    Nov 12 at 4:35












  • added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
    – Ben French
    Nov 12 at 4:38












  • What are BStree and Node? Pointers? Please update your question with this information.
    – Kingsley
    Nov 12 at 4:39












  • I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
    – Ben French
    Nov 12 at 4:43












  • This data organisation makes very little sense. Are these types and signatures given to you?
    – n.m.
    Nov 12 at 5:13















up vote
0
down vote

favorite












My function in c contains objects node, with two attributes Key* a pointer to a key object and int data. The signature of a method is key_comp(key, key), which requires two keys, however the node object contains a pointer to a key. I have tried using node->key and (Node).key however neither work as arguments for this method, how would you go about converting the key pointer to a key for use in a method?



typedef struct 
{
Node tree_nodes;
unsigned char *is_free;
int size;
} BStree_struct;

typedef BStree_struct BStree;

void insert_helper(int i, BStree bst, Node node){
if (i>= (*bst).size){
printf("Out of the range of the tree. n");
return;
}
if ((*bst).is_free[i]==1){
(*bst).tree_nodes[i] = node;
(*bst).is_free[i] = 0;
}else if (key_comp(bst->tree_nodes[i].key, node.key) >0){
insert_helper(2*i,bst,node);
}else if (key_comp(bst->tree_nodes[i].key, node.key) <0){
insert_helper(2*i+1, bst, node);
}
}

typedef struct {char *name; int id;} Key;
typedef struct {Key *key; int data;} Node;
Key *key_construct(char *in_name, int in_id);
int key_comp(Key key1, Key key2);
void print_key(Key *key);
void print_node(Node node);

typedef struct {Node *tree_nodes; unsigned char *is_free;
int size;} BStree_struct;
typedef BStree_struct* BStree;
BStree bstree_ini(int size);
void bstree_insert(BStree bst, Key *key, int data);
void bstree_traversal(BStree bst);
void bstree_free(BStree bst)









share|improve this question




















  • 1




    Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
    – Kingsley
    Nov 12 at 4:35












  • added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
    – Ben French
    Nov 12 at 4:38












  • What are BStree and Node? Pointers? Please update your question with this information.
    – Kingsley
    Nov 12 at 4:39












  • I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
    – Ben French
    Nov 12 at 4:43












  • This data organisation makes very little sense. Are these types and signatures given to you?
    – n.m.
    Nov 12 at 5:13













up vote
0
down vote

favorite









up vote
0
down vote

favorite











My function in c contains objects node, with two attributes Key* a pointer to a key object and int data. The signature of a method is key_comp(key, key), which requires two keys, however the node object contains a pointer to a key. I have tried using node->key and (Node).key however neither work as arguments for this method, how would you go about converting the key pointer to a key for use in a method?



typedef struct 
{
Node tree_nodes;
unsigned char *is_free;
int size;
} BStree_struct;

typedef BStree_struct BStree;

void insert_helper(int i, BStree bst, Node node){
if (i>= (*bst).size){
printf("Out of the range of the tree. n");
return;
}
if ((*bst).is_free[i]==1){
(*bst).tree_nodes[i] = node;
(*bst).is_free[i] = 0;
}else if (key_comp(bst->tree_nodes[i].key, node.key) >0){
insert_helper(2*i,bst,node);
}else if (key_comp(bst->tree_nodes[i].key, node.key) <0){
insert_helper(2*i+1, bst, node);
}
}

typedef struct {char *name; int id;} Key;
typedef struct {Key *key; int data;} Node;
Key *key_construct(char *in_name, int in_id);
int key_comp(Key key1, Key key2);
void print_key(Key *key);
void print_node(Node node);

typedef struct {Node *tree_nodes; unsigned char *is_free;
int size;} BStree_struct;
typedef BStree_struct* BStree;
BStree bstree_ini(int size);
void bstree_insert(BStree bst, Key *key, int data);
void bstree_traversal(BStree bst);
void bstree_free(BStree bst)









share|improve this question















My function in c contains objects node, with two attributes Key* a pointer to a key object and int data. The signature of a method is key_comp(key, key), which requires two keys, however the node object contains a pointer to a key. I have tried using node->key and (Node).key however neither work as arguments for this method, how would you go about converting the key pointer to a key for use in a method?



typedef struct 
{
Node tree_nodes;
unsigned char *is_free;
int size;
} BStree_struct;

typedef BStree_struct BStree;

void insert_helper(int i, BStree bst, Node node){
if (i>= (*bst).size){
printf("Out of the range of the tree. n");
return;
}
if ((*bst).is_free[i]==1){
(*bst).tree_nodes[i] = node;
(*bst).is_free[i] = 0;
}else if (key_comp(bst->tree_nodes[i].key, node.key) >0){
insert_helper(2*i,bst,node);
}else if (key_comp(bst->tree_nodes[i].key, node.key) <0){
insert_helper(2*i+1, bst, node);
}
}

typedef struct {char *name; int id;} Key;
typedef struct {Key *key; int data;} Node;
Key *key_construct(char *in_name, int in_id);
int key_comp(Key key1, Key key2);
void print_key(Key *key);
void print_node(Node node);

typedef struct {Node *tree_nodes; unsigned char *is_free;
int size;} BStree_struct;
typedef BStree_struct* BStree;
BStree bstree_ini(int size);
void bstree_insert(BStree bst, Key *key, int data);
void bstree_traversal(BStree bst);
void bstree_free(BStree bst)






c arrays pointers methods






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share|improve this question













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share|improve this question








edited Nov 12 at 4:45

























asked Nov 12 at 4:33









Ben French

84




84








  • 1




    Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
    – Kingsley
    Nov 12 at 4:35












  • added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
    – Ben French
    Nov 12 at 4:38












  • What are BStree and Node? Pointers? Please update your question with this information.
    – Kingsley
    Nov 12 at 4:39












  • I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
    – Ben French
    Nov 12 at 4:43












  • This data organisation makes very little sense. Are these types and signatures given to you?
    – n.m.
    Nov 12 at 5:13














  • 1




    Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
    – Kingsley
    Nov 12 at 4:35












  • added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
    – Ben French
    Nov 12 at 4:38












  • What are BStree and Node? Pointers? Please update your question with this information.
    – Kingsley
    Nov 12 at 4:39












  • I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
    – Ben French
    Nov 12 at 4:43












  • This data organisation makes very little sense. Are these types and signatures given to you?
    – n.m.
    Nov 12 at 5:13








1




1




Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
– Kingsley
Nov 12 at 4:35






Please add your code to the question, it sounds like you can just use *(node->key), but it's hard to say without seeing the code.
– Kingsley
Nov 12 at 4:35














added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
– Ben French
Nov 12 at 4:38






added the code here is the method, the node contains object of a pointer to a key, however I keep getting errors when compiling
– Ben French
Nov 12 at 4:38














What are BStree and Node? Pointers? Please update your question with this information.
– Kingsley
Nov 12 at 4:39






What are BStree and Node? Pointers? Please update your question with this information.
– Kingsley
Nov 12 at 4:39














I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
– Ben French
Nov 12 at 4:43






I tried the code you suggested and recieved error, invalid argument type of '->' I added the header files from the two files to the question for supplementary information, I will also add the key_comp method
– Ben French
Nov 12 at 4:43














This data organisation makes very little sense. Are these types and signatures given to you?
– n.m.
Nov 12 at 5:13




This data organisation makes very little sense. Are these types and signatures given to you?
– n.m.
Nov 12 at 5:13












1 Answer
1






active

oldest

votes

















up vote
0
down vote



accepted










This is the best I can come up with. It's not clear to me exactly what the code is doing, but having a mix of pointers and object copies is throwing it off a bit.



The key thing to consider is that Node.key is a pointer (to a Key). So to pass these to key_comp(Key a, Key b) you need to de-reference it, thereby converting a Key* to a Key.



void insert_helper(int i, BStree bst, Node node)
{
if (i >= bst.size)
{
printf("Out of the range of the tree. n");
return;
}
if (bst.is_free[i] == 1)
{
bst.tree_nodes[i] = node;
bst.is_free[i] = 0;
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) > 0)
{
insert_helper(2*i, bst, node);
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) < 0)
{
insert_helper(2*i+1, bst, node);
}
}


If it were my code, I'd change key_comp() to take a pair of pointers to Key.






share|improve this answer























  • great works perfectly now !
    – Ben French
    Nov 12 at 5:13











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
0
down vote



accepted










This is the best I can come up with. It's not clear to me exactly what the code is doing, but having a mix of pointers and object copies is throwing it off a bit.



The key thing to consider is that Node.key is a pointer (to a Key). So to pass these to key_comp(Key a, Key b) you need to de-reference it, thereby converting a Key* to a Key.



void insert_helper(int i, BStree bst, Node node)
{
if (i >= bst.size)
{
printf("Out of the range of the tree. n");
return;
}
if (bst.is_free[i] == 1)
{
bst.tree_nodes[i] = node;
bst.is_free[i] = 0;
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) > 0)
{
insert_helper(2*i, bst, node);
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) < 0)
{
insert_helper(2*i+1, bst, node);
}
}


If it were my code, I'd change key_comp() to take a pair of pointers to Key.






share|improve this answer























  • great works perfectly now !
    – Ben French
    Nov 12 at 5:13















up vote
0
down vote



accepted










This is the best I can come up with. It's not clear to me exactly what the code is doing, but having a mix of pointers and object copies is throwing it off a bit.



The key thing to consider is that Node.key is a pointer (to a Key). So to pass these to key_comp(Key a, Key b) you need to de-reference it, thereby converting a Key* to a Key.



void insert_helper(int i, BStree bst, Node node)
{
if (i >= bst.size)
{
printf("Out of the range of the tree. n");
return;
}
if (bst.is_free[i] == 1)
{
bst.tree_nodes[i] = node;
bst.is_free[i] = 0;
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) > 0)
{
insert_helper(2*i, bst, node);
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) < 0)
{
insert_helper(2*i+1, bst, node);
}
}


If it were my code, I'd change key_comp() to take a pair of pointers to Key.






share|improve this answer























  • great works perfectly now !
    – Ben French
    Nov 12 at 5:13













up vote
0
down vote



accepted







up vote
0
down vote



accepted






This is the best I can come up with. It's not clear to me exactly what the code is doing, but having a mix of pointers and object copies is throwing it off a bit.



The key thing to consider is that Node.key is a pointer (to a Key). So to pass these to key_comp(Key a, Key b) you need to de-reference it, thereby converting a Key* to a Key.



void insert_helper(int i, BStree bst, Node node)
{
if (i >= bst.size)
{
printf("Out of the range of the tree. n");
return;
}
if (bst.is_free[i] == 1)
{
bst.tree_nodes[i] = node;
bst.is_free[i] = 0;
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) > 0)
{
insert_helper(2*i, bst, node);
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) < 0)
{
insert_helper(2*i+1, bst, node);
}
}


If it were my code, I'd change key_comp() to take a pair of pointers to Key.






share|improve this answer














This is the best I can come up with. It's not clear to me exactly what the code is doing, but having a mix of pointers and object copies is throwing it off a bit.



The key thing to consider is that Node.key is a pointer (to a Key). So to pass these to key_comp(Key a, Key b) you need to de-reference it, thereby converting a Key* to a Key.



void insert_helper(int i, BStree bst, Node node)
{
if (i >= bst.size)
{
printf("Out of the range of the tree. n");
return;
}
if (bst.is_free[i] == 1)
{
bst.tree_nodes[i] = node;
bst.is_free[i] = 0;
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) > 0)
{
insert_helper(2*i, bst, node);
}
else if (key_comp(*(bst.tree_nodes[i].key), *(node.key)) < 0)
{
insert_helper(2*i+1, bst, node);
}
}


If it were my code, I'd change key_comp() to take a pair of pointers to Key.







share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 12 at 5:12

























answered Nov 12 at 5:07









Kingsley

2,07811022




2,07811022












  • great works perfectly now !
    – Ben French
    Nov 12 at 5:13


















  • great works perfectly now !
    – Ben French
    Nov 12 at 5:13
















great works perfectly now !
– Ben French
Nov 12 at 5:13




great works perfectly now !
– Ben French
Nov 12 at 5:13


















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