don't quite understand this line...

[ahming]

currently reading about lists.

i have this line of code in an insertion function.

if (lptr->list[pos]>item)

i have an array containing this for example:

0: Deer 1:Fox 2: Dog 3:Cat

lets say list[pos] is Fox and item is Cat.

what happens?

i thought you could only compare strings with the string library functions

sorry there is no ']' after item. yes they are in the same array

[Stoned_Coder]

list is an array that is a member of some structure pointed to by the pointer lptr and you are comparing the pos element of that array with item using a greater than operator.

Sure its c and not c++? in c++ operators can be overloaded to do whatever. post more code.

[Karthur]

You must have copied it wrong, or its bad code. There is an unmatched "]" in there.
Without that it would compare 2 addresses (usually a meaningless action unless in the same array). Try again.

[ahming]

so i could have instead of

lptr->list[pos] < item

could i have

pos instead of lptr->list[pos]? seeing as it gives the position.

well here is the full code:

void Insert(List *lptr, char item){
	int pos, current;
 
	if(IsFull(lptr))
	{
		fprintf(stderr, "List is full.");
		exit(1);
	}
 
	for(pos = 0; pos < lptr->count; pos++)
	{
		if(lptr->list[pos] > item)
			break;
	}
 
	current = lptr->count - 1;
	while (current >= pos)
	{
		/* Copy the element into the next position along */
		lptr->list[current+1] = lptr->list[current];
		current--;
	}
 	lptr->list[pos] = item;
	lptr->count++;
}

i want to insert an 'item' say EMU at position 2.
how does lptr->[pos] < item work if item is not already in the array, seeing as it compares the positions

[Karthur]

You haven't shown how List is defined, but apparently its something like:

typedef struct {
      ...
      int count;
      char[99] list; /* or some other arbitrary length */
      ...
} List;

because your item is a single char. For your code to work, lptr->list[pos] should also be a char, and the validity of the comparison is obvious, but you'll have a hard time getting EMU passed in as an item in a single char.

I think you copied code that was intended for a different purpose than you are trying to use it. It is now clear what list[pos] and item are, and you are not comparing 2 pointers or addresses, you are comparing 2 chars. All this does is take in characters one at a time and put them in a string keeping the string in ascii value order. (Actually just a char array, because its not nul terminated except by accident.)

[quzah]

This isn't correct:

char[99] list; /* or some other arbitrary length */

It would be:

char list[99]; /* or some other arbitrary length */

Quzah.