help (urgent)

Posted on 1997-04-30
Last Modified: 2010-04-10
I have a little problem concerning arrays.

Say I have an array called Numbers and it has 10 elements :

array pointer       contents
    0                  3
    1                  8
    2                  12
    3                  66
    4                  7
    5                  128
    6                  1001
    7                  45
    8                  63
    9                  1137

To access for example the third elemnt in the array, I have to write, cout << Numbers[2] << endl ;
and that would print 12.
But if I had two variables, x = 1 and y = 2 then typing, cout << Numbers[x+y] does not print 12, instead it prints 3.

Does anyone know why that is, and how can I correct this so that it prints the contents instead.


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Question by:9628657

Expert Comment

ID: 1163124
Could use some source code. Is x and y an int? how are you defining x and y?

Author Comment

ID: 1163125
Yes, x and y are defined as integers.

Expert Comment

ID: 1163126

The way you discribe it there should be no problem... Can you post more of your code?



Expert Comment

ID: 1163127
What compiler do you use?
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Expert Comment

ID: 1163128
It is not possible to find error in your code until you post this code!

Accepted Solution

jmmougeolle earned 10 total points
ID: 1163129
That's normal you got that result...

Your X+Y value give a result of 3 So Numbers[3] is exactely 3!
What you want to have as a X+Y result is 2!!! Not 3! SO Numbers[2] will give you 12, and that's what you are expecting!

In fact, the error come from the 0 based organisation of your coordinate!

Don't hesitate to ask for more info!

May the MFC be with you! strikes back!

Expert Comment

ID: 1163130
The problem you posted is NOT normal (as jmmougeolle said). In fact, x+y = 3, and therefore Numbers[x+y] should give 66, not 12 as you're expecting. But I'd recommend posting most of your program, so that I may be able to find the actual error.

Expert Comment

ID: 1163131
jmmougeolle said:

>That's normal you got that result...

>Your X+Y value give a result of 3 So Numbers[3] is exactely 3!
>What you want to have as a X+Y result is 2!!! Not 3! SO >Numbers[2] will give you 12, and that's what you are expecting!

>In fact, the error come from the 0 based organisation of your >coordinate!

I do not believe this answer to be correct for the following reason: If you want x+y to give you the answer 2 so the number  12 will be displayed, why was 66 not displayed when x+y summed to 3? 66 is the value in element 3 of the array and that is what should have been displayed if jmmougeolle's theory is correct. Just a offense is intended.

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