Thread: I print something and at the next line it points to NULL

I am sorry but i didn't in order not to tire you..
Definitions

Code:

typedef struct TStoixeioyTree{/*TStoixeioyTree.h*/
    char* name;
    char* surname;
}TStoixeioyTree;
typedef struct typos_komvou * typos_deikti;/*ch8_BSTpointer.h*/

typedef struct typos_komvou{ /*ch8_BSTpointer.c*/
	TStoixeioyTree dedomena;
	typos_deikti apaidi;
	typos_deikti dpaidi;
} typos_komvou;

struct tree_struct{/* den exw idea pou pane ta gamidia */
	typos_deikti node;
}tree_struct;

typedef struct tree_struct *structPtr;

Create

Code:

structPtr Tree_dimiourgia()
{
    structPtr tree;
    tree=malloc(sizeof(structPtr));
	tree->node=NULL;
	return tree;
}

Insert

Code:

void Tree_eisagogi(structPtr treePtr , TStoixeioyTree stoixeio, int *error)
{
    typos_deikti origin,temp;
    origin=treePtr->node;
    
	if(Tree_keno(treePtr))
	{
		temp=malloc(sizeof(typos_komvou));
		if(temp==NULL)
		{
			*error=1;
			return;
		}
		treePtr->node=temp;
		treePtr->node->dedomena.surname=malloc(strlen(stoixeio.surname)+1 );
        treePtr->node->dedomena.name=malloc(strlen(stoixeio.name)+1 );
		TStree_setValues(&((treePtr)->node->dedomena), stoixeio);
		treePtr->node->apaidi=NULL;
		treePtr->node->dpaidi=NULL;
	}
	else if(TStree_mikrotero(stoixeio, treePtr->node->dedomena))
	{
		treePtr->node=treePtr->node->apaidi;
		Tree_eisagogi(treePtr , stoixeio, error);
	}
	else if(TStree_megalytero(stoixeio, treePtr->node->dedomena))
	{
        treePtr->node=treePtr->node->dpaidi;
		Tree_eisagogi(treePtr , stoixeio, error);
	}
	else if(TStree_iso(stoixeio, treePtr->node->dedomena))
	/* These two lines of code are mine.Without this two,if we had a name twice then function would set error=1*/
	    return;
	else
		*error=1;
	if(i!=1)            /* i is a global var.*/
		treePtr->node=origin;
}

Print

Code:

void nodesprint(structPtr treePtr, FILE *fp)                     /* Print tree nodes */
{
	typos_deikti origin;
	origin=treePtr->node;
	if (Tree_keno(treePtr)) {                      /* If tree is not empty */
	treePtr->node=treePtr->node->apaidi;
    nodesprint(treePtr,fp);               /* Print left subtree */
    fprintf(fp,"%s %s\n", treePtr->node->dedomena.surname , treePtr->node->dedomena.name);/* Print root node */
    treePtr->node=treePtr->node->dpaidi;
    nodesprint(treePtr,fp);            /* Print right subtree */
 }
  treePtr->node=origin;
}

Empty tree

Code:

int Tree_keno(structPtr treePtr)
{
 	return (treePtr->node==NULL);
}