hi
I was doing a program for inserting a item in to the linked list..i have to insert the item before the fist one..something is wrong with my ins_first() function
just help me out
Code:void ins_first(node *p) { int x; node *p1; p1=(node*)malloc(sizeof(node)); printf("\nEnter the number to be inserted in the begining: "); scanf("%d",&x); p1->number=x; p1->next=p; p=p1; return ; }
On it's own it seems mainly fine, what errors are you getting?
it's ironic considerate rarity patron of love higher knowledge engulfs me...
Is "p" the current head of the linked list? Could you use less meaningful variable names?
Code:void ins_first(node **p) { int x; node *p1; p1 = (node*) malloc( sizeof(node) ); /* Should check your malloc worked !! */ printf("\nEnter the number to be inserted in the begining: "); scanf("%d",&x); /* Don't use scanf */ p1->number = x; p1->next = (*p); *p = p1; return; }
Oh of course, I always get confused on this one.
SKeane is correct, but you need to probably change your call to the function.
Given your program looks like this:
Code:node * head; ins_node( &head );
The original problem is that while you were passing a pointer - you were actually passing a variable that holds the address as it's value - you were not passing the address itself. So, you need to pass the address, of the address - if that makes sense. :P
it's ironic considerate rarity patron of love higher knowledge engulfs me...
> p1=(node*)malloc(sizeof(node));
Don't cast malloc in C
See the FAQ
As everyone has said, you need to return the modified result.
I find this approach convenient in that it saves too many *'s
Then you doCode:node *ins_first(node *p) { //... return p; }
Code:list = ins_first( list );
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
