Thread: Array Index: A simple question?

Using 0 to n is simpler because it is easier to visualise an offset. For instance int foo[x] is offset (sizeof(int) * x) bytes from foo itself. So foo[1] would be sizeof(int) bytes away from foo, and foo[0] would be 0 bytes away from foo.

there is nothing wrong with starting the index value from 1 or 0. the only resaon if you start from 0 is that the compiler internally starts the indexing from the 0 and more over you not wasting memory. let me give an example lets take aand set of numbers and store that in a array
10 20 30 40 50
letd insert these values inside and arrat starting the index value from 0

Code:

int array[5];

[10] [20] [30] [40] [50]
0      1      2     3     4     -------->  while(i<5)

starting the index value from 1

Code:

[ ] [10] [20] [30] [40] [50]
0  1      2       3    4      5 ----------> while(i<=5);

can u now find out the differece between the two indexing style, in the former one u starting at 0 and u goign up to 4, but with the later you start with the 1 and go up to 5

with the latter u are just wasting one element that index 0. but still be programmer use the later style as the real work speaks from 1 not from 0

ssharish2005

i prefer starting from 0

ssharish2005

Originally Posted by logicwonder

This is not the point. I am concerned about accepting position inputs and displaying position outputs. I always use the correct method of indexing 0 to n-1. But when it comes to input/output what about giving a pseudo index (i.e position+1)?

As long as you are consistent, and as long as you keep the "guts" hidden, then in my opinion it shouldn't matter.

As I understand it, you're basically talking about representing the position to the user as postion + 1. As long as you ALWAYS do this, and don't get confused (believe me, it can happen), then it's my opinion that it is fine.

Nothing wrong with hiding implementation details from your interface. In fact, in most cases, it is highly desirable.

Thank you harish for your view.

Hello ,

I would prefer 0 to n-1 based indexing.

The user will be most concerned about the position and would not be concentrating on index that represents the position.
So while getting the input and displaying the same we can apply pseudo masking (implementation of program).

so here it lies in the hands of programmer to apply the pseudo masking and thus it become user friendly and more flexible.

if you're writing a program that lets users create array's and then allows the user to enter content into the array, I'd certainly make it look like 1-n. It'd be more confusing for him if he had to enter a given value to the 0th space in the array he's working on. for a user it makes much more sense to start in the 1st space and finish on the nth...

Hello,

I don't understand ??

even if u making users to create arrays then for users it should reflect from 1 to n-1 and the actual implementation will be in the program implementation...So what will happen if do pseudo masking for end users and 0 to n in coding..???

Originally Posted by geajith

Hello,

I don't understand ??

even if u making users to create arrays then for users it should reflect from 1 to n-1 and the actual implementation will be in the program implementation...So what will happen if do pseudo masking for end users and 0 to n in coding..???

wrong, for users it'll be 1 to n, not n-1

All you're doing is hiding what actually happens from the user to make it easier for them to understand...