problem in storing data in a binary search tree

hi all,
i want to read strings from a file and store them in a binary search tree. i can print the strings to the screen, but when i try to store them in the tree, only last string is stored in the root of the tree, others vanish. code is below

Code:

---


#include <stdio.h>
//#include <iostream.h>
#include <string.h>
#include <malloc.h>
//#include <string> --cpp only

typedef struct BinaryNode
{
        char* data;
        struct BinaryNode* left;
        struct BinaryNode* right;

}nodeType;

nodeType* root = NULL;
 
void insertToTree(char*);

nodeType* insertToNode(char*, nodeType*);

int isEmpty();

void printTree();

void printNode(nodeType*);

int main()
{
       
        FILE* inputFile = fopen("deneme.txt", "r");       
       
        char* lino;

        while( !feof(inputFile)){       
               
                char line[10];
                lino = (char*)malloc(sizeof(char));
                lino = fgets(line, sizeof(line), inputFile);
                insertToTree( lino  );
                printf(lino);
        }
        printf("\n");       
        printf("printing whole tree \n");
        printTree();
        fclose(inputFile);
       
                return 0;       
}

void insertToTree(char* x)
{       
        root = insertToNode(x, root);
}

nodeType* insertToNode(char* x, nodeType* t){
       
        if (t == NULL) {
               
                t = ( nodeType * )malloc(sizeof( nodeType ) );               
                t->data = x;
                t->left = NULL;
                t->right = NULL;
               
        }

        else if(strcmp(x, t->data) < 0){
               
                t->left = insertToNode(x, t->left);

        }

        else if(strcmp(x, t->data) > 0){

                t->right = insertToNode(x, t->right);

        }

        else
                ;
       
        return t;
}

void printTree(){
       
        if( isEmpty( ) != 0)
                printf( "Empty tree\n" );
    else
        printNode( root );       
}

int isEmpty( )
{
        int TRUE = 5;
        int FALSE = 0;
       
        if (root == NULL)
                return TRUE;
        else
                return FALSE;
}

void printNode( nodeType* t )
{
        if( t != NULL )
    {
                printNode( t->left );
        printf("data: %s\n", t->data );
        printNode( t->right );
        }
}

---

Well, I get the unhandled exception here:

Code:

---

else if(strcmp(x, t->data) < 0){

---

To me that means either x or t->data are NULL and trying to be accessed. and since you check t, and you never check the return from malloc or fgets for NULL I would be willing to wager that your problem lies in here:

Code:

---

while( !feof(inputFile)){   
       
        char line[10];
        lino = (char*)malloc(sizeof(char));
        lino = fgets(line, sizeof(line), inputFile);
        insertToTree( lino  );
        printf(lino);
    }

---

Unless you are using a C++ compiler you should never cast malloc(). This is why.

This is a better read loop:

Code:

---

lino = (char*)malloc(sizeof(line));

while((lino = fgets(line, sizeof(line), inputFile))){   
    insertToTree( lino  );
    printf(lino);
}

---

Also when you add your node you never initialize your data variable or allocate any space for it. You add node should look like:

Code:

---

t->data = (char*)malloc(sizeof(*x));
if(t->data != NULL)
    strcpy(t->data,x);

---

This will now print out the tree.

thanks a lot andy, it works very well

Code:

---

#include <stdio.h>
//#include <iostream.h>
#include <string.h>
#include <malloc.h>
//#include <string> --cpp only

---

Please make up your mind as to whether you're compiling C or C++.
If it's C, then you need to
a) stop casting malloc
b) #include <stdlib.h>
There is no standard header called malloc.h

Code:

---

lino = (char*)malloc(sizeof(line));

while((lino = fgets(line, sizeof(line), inputFile))){

---

This is just a memory leak - there is no need to allocate anything to lino
In fact, it's a useless variable, since you may as well just write

Code:

---

while( fgets(line, sizeof(line), inputFile) ) {   
    insertToTree(line);
    printf(line);
}

---

>

Code:

---

int isEmpty( )
{
    int TRUE = 5;
    int FALSE = 0;
   
    if (root == NULL)
        return TRUE;
    else
        return FALSE;
}

---

What an utterly bizarre value for true - most people (and the language) use the value 1.
This function can be reduced to

Code:

---

int isEmpty( )
{
    return root == NULL;
}

---

well i started programming in c very recently, after programming in java for sometime. anyway thx for your help, below is the last version of my code

Code:

---

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

typedef struct BinaryNode
{
        char* data;
        struct BinaryNode* left;
        struct BinaryNode* right;

}nodeType;

nodeType* root = NULL;
 
void insertToTree(char*);

nodeType* insertToNode(char*, nodeType*);

int isEmpty();

void printTree();

void printNode(nodeType*);

int main(int argc, char* argv[])
{
        //char* fileName = argv[1];
        char* fileName = "deneme.txt";
       
        FILE* inputFile = fopen(fileName, "r");
                       
        char line[1000];       
               
        while( fgets(line, sizeof(line), inputFile) ){
               
                insertToTree( line  );
                printf(line);
        }
        printf("\n");       
        printf("printing whole tree \n");
        printTree();
        fclose(inputFile);
       
        return 0;       
}

void insertToTree(char* x)
{       
        root = insertToNode(x, root);
}

nodeType* insertToNode(char* x, nodeType* t){
       
        if (t == NULL) {               
               
                t = malloc(sizeof (nodeType) );
                t->data = malloc(sizeof(*x));
               
                //if(t->data != NULL)
                strcpy(t->data,x);
               
                t->left = NULL;
                t->right = NULL;
               
        }

        else if(strcmp(x, t->data) < 0){
               
                t->left = insertToNode(x, t->left);

        }

        else if(strcmp(x, t->data) > 0){

                t->right = insertToNode(x, t->right);

        }

        else
                ;
       
        return t;
}

void printTree(){
       
        if( isEmpty( ) )
                printf( "Empty tree\n" );
    else
        printNode( root );       
}

int isEmpty( )
{
       
        return root == NULL;
}

void printNode( nodeType* t )
{
        if( t != NULL )
    {
                printNode( t->left );
        printf("data: %s\n", t->data );
        printNode( t->right );
        }
}

---

i checked the code with valgrind (1.9.6) and it gives these errors

Invalid write of size 1
==2143== at 0x4015FBE9: strcpy (in /usr/lib/valgrind/valgrind.so)
==2143== by 0x804864D: insertToNode (in /home/edip/Documents/cs342-os/hw1.exe)
==2143== by 0x8048604: insertToTree (in /home/edip/Documents/cs342-os/hw1.exe)
==2143== by 0x8048581: main (in /home/edip/Documents/cs342-os/hw1.exe)
==2143== Address 0x40F30201 is 0 bytes after a block of size 1 alloc'd
==2143== at 0x4015F3AF: malloc (in /usr/lib/valgrind/valgrind.so)
==2143== by 0x8048638: insertToNode (in /home/edip/Documents/cs342-os/hw1.exe)
==2143== by 0x8048604: insertToTree (in /home/edip/Documents/cs342-os/hw1.exe)
==2143== by 0x8048581: main (in /home/edip/Documents/cs342-os/hw1.exe)

error summary and leak summary is

ERROR SUMMARY: 299 errors from 24 contexts (suppressed: 0 from 0)
==2143== malloc/free: in use at exit: 323 bytes in 38 blocks.
==2143== malloc/free: 39 allocs, 1 frees, 687 bytes allocated.
==2143== For counts of detected errors, rerun with: -v
==2143== searching for pointers to 38 not-freed blocks.
==2143== checked 3364000 bytes.
==2143==
==2143== LEAK SUMMARY:
==2143== definitely lost: 0 bytes in 0 blocks.
==2143== possibly lost: 0 bytes in 0 blocks.
==2143== still reachable: 323 bytes in 38 blocks.
==2143== suppressed: 0 bytes in 0 blocks.