Experts please find the bug in this sorting list program
Hi i have a bug in my program that i have been trying to find but i cant find it.I am trying to sort my data as i pass it in into a double linked list.My test data is 7,5,1. it works when there are only two numbers but when i increased it to three nodes this is what happens
1,7. my five gets overwritten.
Code:
struct node{
char key;
struct node *next;
struct node *previous;
};
struct listset{
int length;
struct node *head;
struct node * tail;
struct node *iterator;
};
struct listset * listset_new(){
struct listset *p =(struct listset*) malloc(sizeof(*p));
p->head=NULL;
p->tail=NULL;
p->iterator=NULL;
p->iterator=NULL;
return p;
}
/* add new item before current item. if the iterator ia at end of the
list then add item to end of list */
void list_add_before_current(struct listset * p,char item){
struct node * temp = (struct node*)malloc(sizeof (*temp));
if(list_at_end(p)){
//at end of list
// if(p->iterator->previous!=NULL&& p->iterator->next==NULL){
temp->next=NULL;
p->tail->next=temp;
temp->key=item;
temp->previous=p->tail;
p->tail=temp;
// }
}
//if only one element in the list
else if(p->iterator->previous==NULL&&p->iterator!=NULL){
p->head=temp;
temp->key=item;
temp->next=p->iterator;
}
//anywhere in the list
else
{
temp->key=item;
p->iterator->previous->next=temp; //pointing my former previous node next to my new node
p->iterator->previous=temp; //iterator previous now points to my new node
temp->previous=p->iterator->previous; // new node previous points tom my currents iterator previous
temp->next=p->iterator; //new node next points to my iterator
}
}
void list_move_to_start(struct listset *p){
while(p->iterator->previous!=NULL){
p->iterator=p->iterator->previous;
}
}
void listset_add(struct listset * t, char item){
struct listset *a=t;
int found=0;
struct node *temp= (struct node*)malloc(sizeof(*temp));
if(t->head==NULL)
{
a->head=temp;
a->tail=temp;
temp->key=item;
temp->previous=NULL;
temp->next=NULL;
a->iterator=temp; //when first element is added .iterator becomes my temp
}
else {
while(a->iterator!=NULL && found!=1){
if(item<a->iterator->key){
list_add_before_current(a, item);
found=1;
list_move_to_start(a);}
else
a->iterator=a->iterator->next;
}//iner while
if(a->iterator==NULL){
list_add_before_current(a, item);
list_move_to_start(a);
}
}//else
}
//checking if a list is empty
int isEmpty(struct listset *p){
if(p->head==NULL)
return 1;
else
return 0;
}
//removing an item from the end of the list
void list_popBack(struct listset *p){
if(p->tail->previous==NULL)
{
free(p->tail);
p->head=NULL;
}
else {
p->tail->previous->next=NULL;
free(p->tail);
}
}
void list_write_out(struct listset *p){
struct node *current=p->head;
while(current!=NULL){
printf("%d ",current->key);
current=current->next;
}
}
/* move the iterator to the next item in the list */
void list_move_to_next(struct listset * p){
p->iterator=p->iterator->next;
}
int list_get_current(struct listset * p){
int c=0;
c= p->iterator->key;
return c;
}
/* set the value of the current value of the list */
void list_set_current(struct listset * p, char item){
p->iterator->key=item;
}
/* delete the current item in the list */
void list_delete_current(struct listset * p){
if(p->iterator->previous==NULL)
{
free(p->iterator);
p->head=NULL;
}
else {
p->iterator->previous->next=p->iterator->next;
free(p->iterator);
}
}
/* check has the iterator moved past last item in list;
always true if list is empty */
int list_at_end(struct listset * p){
if( (p->iterator==NULL && !isEmpty(p) )){
return 1;
//printf("at end of list");
}
else {
// printf(" notat end of list");
return 0;}
}
int main(int argc, char** argv) {
struct listset *src1;
struct listset *src2;
struct listset *destination;
src1=listset_new();
src2=listset_new();
destination=listset_new();
char buffer[100];
char x;
int choice;
listset_add(src1, 7);
listset_add(src1, 5);
listset_add(src1, 1);
