Linked Lists please help!!!
Hey everyone, i am sending this message because i have a problem with my program in Linked Lists. All of a sudden i can't print my list. Actually i have my insert function where i add the numbers and it seems to work ok.
I tried so many times to change my function but still nothing. I have my head and tail pointing to NULL (struct Node *head = NULL, struct Node *tail = NULL) outside main(). I have my code and please i will appreciate it so much if you explain me what is the problem here and every time my function print_list() says the list is empty.
Code:
struct Node //My struct
{
int value;
struct Node *next;
};
struct Node *head = NULL;
struct Node *tail = NULL;
void insert(struct Node *, int);
void Delete(struct Node *);
void empty_list(struct Node *);
void print_list(struct Node *);
struct Node *reverse(struct Node *);
int size(struct Node *);
int main() //Start of main() function
{
int choice, pl;
int done = -1;
int num, rev;
while(done != 0) // I want to have a menu so the user has to choose one of the options
{
printf(" MENU \n");
printf(" --------------------------- \n");
printf(" 1. Insert an element in the list \n");
printf("\n");
printf(" 2. Delete an element from the list \n");
printf("\n");
printf(" 3. Print the length of the list \n");
printf("\n");
printf(" 4. Print if the list is empty or not \n");
printf("\n");
printf(" 5. Print the elements of the list \n");
printf("\n");
printf(" 6. Reverse list\n");
printf(" \n");
printf(" 7. Exit \n");
printf("\n");
printf(">> Give your choice: ");
scanf("%d", &choice);
printf("\n");
switch(choice)
{
case 1:
printf("\nGive a number: ");
scanf("%d", &num);
printf("\n");
insert(&head, num);
break;
case 2:
Delete(&head);
break;
case 3:
pl = size(&head);
printf("\nThe list has : %d elements", pl);
printf("\n\n");
break;
case 4:
empty_list(&head);
break;
case 5:
print_list(head);
break;
case 6:
rev = reverse(head);
printf("The list in reverce order is: %d ", rev);
printf("\n");
printf("\n");
break;
case 7:
done == 0;
break;
default:
printf("Wrong choice");
printf("\n");
}
}
return 0;
}//end of main() function
//From this part and so on i started to create my functions
void insert(struct Node *head, int num) //insert function
{
struct Node *temp1;
temp1=(struct Node*)malloc(sizeof(struct Node));
temp1 = head;
while(temp1->next!=NULL)
temp1 = temp1->next;
struct Node *temp;
temp = (struct Node*)malloc(sizeof(struct Node);
temp->value = num;
temp->next = NULL;
temp1->next = temp;
printf("\nYour number has been inserted in your list \n");
printf("\n\n");
}
void Delete(struct Node *head)//Delete function
{
struct Node *last;
last = (struct Node *)malloc(sizeof(struct Node));
last = head;
struct Node *previous_last;
previous_last = (struct Node *)malloc(sizeof (struct Node));
while(last->next != NULL)
{
previous_last = last;
last = previous_last->next;
}
previous_last->next = NULL;
free(last);
printf("The element has been deleted \n");
printf("\n");
}
void empty_list(struct Node *head)//empty_list funcion
{
struct Node *pointer = head;
if (pointer == NULL)
{
printf("The list is empty");
printf("\n");
}
else
{
printf("The list is not empty");
printf("\n");
}
}
struct Node *reverse(struct Node *head) //reverse function
{
struct Node *current = NULL;
struct Node *temp;
struct Node *first;
while (first!= NULL)
{
temp = first;
first = first->next;
temp->next = current;
current =temp;
}
return current;
}
void print_list(struct Node *head)//print_list fuction
{
struct Node *pointer = head;
if(pointer==NULL)
{
printf("The list is empty");
printf("\n");
}
else
{
printf("The list is:");
while(pointer->next != NULL)
{
("%d", pointer->value);
printf("\n");
pointer = pointer->next;
}
}
}
int size(struct Node *head)//size (of the list, how many elements are in the list) function
{
struct Node *temp = head;
int counter = 0;
while(temp)
{
counter = counter + 1;
temp = temp->next;
}
return counter;
}
Thank you
Sparse Matrices in C help
Can anyone tell me how a sparse matrix work with linked lists? I truly can't understand. Now i have to make the array (insert values in it) and print it.
I have tried to find out about it but nothing.
All help will be appreciate.
Thanx!!
