Problem passing data between functions

I have tried to create a binary tree structure for storing data, but I can't seem to get the program to compile. It flags up an error when returning a from the function createtree and when assigning this result to a in the main program.

They are both data type tree which is created at the start, and both are pointers. I cannot understand why the program cannot return/assign these two values.

It is probably something very simple but I would be very grateful for the help.

Code:

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

typedef struct tree{
  char thisnode[50];
  struct tree *leftnode;
  struct tree *rightnode;
}Tree;

Tree *makenode(char *in, Tree *l, Tree *r){
  Tree *t = malloc(sizeof(Tree));
  t->leftnode = l;
  t->rightnode = r;
  strncpy(t->thisnode, in, 9);
  return t;
}

Tree *insertnode(Tree *root, char *data){
  if (root == NULL) {
    root = makenode(data, NULL, NULL);}
  else if(strcmp(data, root->thisnode)<0){
    root->leftnode = insertnode(root->leftnode, data);}
  else{
    root->rightnode = insertnode(root->rightnode, data);}
  return root;
}

char *search(Tree *root, char *number){
  if (root == NULL){
    return "Not Found";}
  else if(strcmp(number, root->thisnode) == 0){
    return root->thisnode;}
  else if(strcmp(number, root->thisnode) < 0){
    return search(root->leftnode, number);}
  else {
    return search(root->rightnode, number);
  }
}

Tree createtree(){
    char i[25];
    int j;
    Tree *a = NULL;
    while (i[0] != '.'){
          for(j = 0; j < 25; j++){
                i[j] = getchar();
                a = insertnode(a,i);               
          }
    }
    return a;
}

int main()
{
    Tree *a = NULL;
    a = createtree();
   
    if(a != 0) {
    printf("\n");
    while(a->leftnode != 0) {
        printf("%s", a->thisnode);
        a = a->leftnode;
    }
    printf("%s", a->thisnode);
}
    return 0;
}

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Code:

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Tree createtree(){

---

Code:

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    Tree *a = NULL;

---

Code:

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return a;

---

notice anything wrong?

oh god, I can't believe I was that stupid.

Thanks a lot for the help

also I'm not seeing how this is gonna do what you want

Code:

---

    while (i[0] != '.'){
          for(j = 0; j < 25; j++){
                i[j] = getchar();
                a = insertnode(a,i);               
          }
    }

---

i is an uninitialized array, yet you test it against '.'
then the way I see it, if the user doesn't enter . at the first iteration. this will never stop untill on the 25th, 50th, 75th ... 25*ith (I think that math is right) iteration a . is entered. is this intended?

::edit nope that math is wrong...its 26th, 52nd, 78th, 26*ith...I think thats right now

yeh I know thats the next problem I discovered, i've replaced the for loop with a second while loop.

Although it doesn't seem to exit this loop, Does getchar() scan newline characters in? if not thats where my next problem lies. I have included the modified function createtree below just incase it helps.

Code:

---

Tree createtree(){
   
    char i[50];
    int j;
    Tree *a = NULL;
    while (i[0] != '.'){
          j = 0;
          while (i[j] != '\n'){
                i[j] = getchar(); 
                j++;             
          }
    a = insertnode(a,i);
    }
    return *a;
}

---

the way you have it yes
ie.
if you had

Code:

---

for (i = 0; i < some size; i++)
{
      array[i] = getchar();
}

---

every other position would be newline

edit:: when exactly do you want it to stop taking new characters? when . is entered?

yes, I want it to place each line into a different node on the tree and then stop when a '.' character is entered.

edit:

I have changed the code again so it now exits the loop, although I now get a segmentation fault when I try to return *a to the main function.

I know this is a memory issue, I have allocated the space for the tree in the *makenode function so I am confused as to what the problem is.

Here is the new code

Code:

---

Tree createtree(){
   
    char i[50];
    int j;
    Tree *a = NULL;
    while (i[0] != '.'){
          j = -1;
          while (i[j] != '\n'){
                j++;
                i[j] = getchar(); 
                             
          }
    a = insertnode(a,i);
    }
    return *a;
}

---

Look the function signature, it isn't returning a Tree * as you expect.

you could use a for loop then say
ch[i] = getchar();
if ch[i] != '.' then insert
else break;
flush stdin (the correct way of course)

I think that would work. But someone else probably has a really neat way to do this. I'm sure there is one, I just can't think of it.

hmmm, I think I'm a little confused after looking over this again. each node contains a string? but your trying to insert nodes after every character you get.
is a node supposed to just contain 1 char? or a string