Thread: Reversing elements in an array - pointers or no?

  1. #1
    Registered User
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    May 2020
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    Reversing elements in an array - pointers or no?

    DISCLAIMER: I don't want direct guidance of what to do, just to be offered some (probably cryptic) direction.

    I've been tasked with a programme to reverse the elements in an array

    Code:
    for (int i = 0; i <= height; i++)    
              {
               for (int j = 0; j <= width; j++)
              {
                //takes jth pixel into temp
                var temp = image[i][j];
                
                //puts last pixel into jth place
                image[i][j] = image[i][j-1];
                
                //puts first pixel into last place
                image[i][j-1] = temp;
            }
        }
    This chunk of code seemingly swaps the first and last elements, but obviously not the rest of them. Can someone point me in the right direction?

  2. #2
    Registered User
    Join Date
    May 2012
    Posts
    421
    To reverse an array, iterate ove half of it, swapping the element with the one at the reflection point. Don't iterate over the full array or you will undo what you just did.
    I'm the author of MiniBasic: How to write a script interpreter and Basic Algorithms
    Visit my website for lots of associated C programming resources.
    https://github.com/MalcolmMcLean


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