Switching Array Elements

This is a discussion on Switching Array Elements within the C Programming forums, part of the General Programming Boards category; Ok guys I'm a newb so go easy on me. I am trying to reverse the corresponding elements in the ...

  1. #1
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    Switching Array Elements

    Ok guys I'm a newb so go easy on me. I am trying to reverse the corresponding elements in the array I created. I don't understand why this isn't working.

    Code:
    #include <stdio.h>
    int main ()
    {
    
    const int n=6;
    int k;
    int temp;
    int a[n];
    
    for (k=0; k<n; k++) {
        a[k]=0;
        a[k]=k+1;
    }
    printf("Before\n");
    for (k=0; k<n; k++) {
        printf("%d\n" , a[k]);
    }
    for (k=0; k<n; k++) {
        temp=a[k];
        a[k]=a[n-(k+1)];
        a[n-(k+1)]=temp;
    }
    printf("After\n");
    for (k=0; k<n; k++) {
        printf("%d\n" , a[k]);
    }
    
    }

  2. #2
    Code Goddess Prelude's Avatar
    Join Date
    Sep 2001
    Posts
    9,796
    >I don't understand why this isn't working.
    Code:
    for (k=0; k<n; k++) {
        temp=a[k];
        a[k]=a[n-(k+1)];
        a[n-(k+1)]=temp;
    }
    This loop has two parts. The first part completely reverses the array from the beginning to the middle. The second part completely reverses the array from the middle to the end. What happens when you reverse an array twice?
    My best code is written with the delete key.

  3. #3
    Registered User
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    Nov 2006
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    2
    Duh! That makes complete sense! Thank you.

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