quick sorting a char array in C

Question

I copy an

int

array in order to try the quick sort algorithm from here.

Then I change the type of the array to

char

. Here is the edited code:

extern void quickSortChar(char a[], int left, int right)

{

    int j;

    if (left < right)

    {

        j = partition(a, left, right);

        quickSort(a, left, j - 1);

        quickSort(a, j + 1, right);

    }

}



static int partition(char a[], int left, int right)

{

    int pivot, i, j, t;

    pivot = a[left];

    i = left; j = right + 1;



    while (1)

    {

        do i++; while (a[i] <= pivot && i <= right);

        do j--; while (a[j] > pivot);

        if (i >= j) break;

        t = a[i]; a[i] = a[j]; a[j] = t;

    }

    t = a[left]; a[left] = a[j]; a[j] = t;

    return j;

}



void main()

{

    char arr[] = "bacgd";

    puts(arr);

    quickSortChar(arr, 0, strlen(arr) - 1);

    puts(arr);

    system("pause");

}

I expect the output to be:

abcdg

, but output is:

abcgd

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Answer 1

You're calling quickSort() recursively (wrong function name) inside quickSortChar().

After fixing this bug, it runs and produces good output on my machine:

$ ./program
bacgd
abcdg

quick sorting a char array in C

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