JackJobs JackJobs - 1 year ago 169
C Question

quick sorting a char array in C

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

Answer Source

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
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