 # function for quicksort in c

```#include

void swap(int* a, int* b)

{

int t = *a;

*a = *b;

*b = t;

}

int partition (int arr[], int low, int high)

{

int pivot = arr[high];

int i = (low - 1);

for (int j = low; j <= high- 1; j++)

{

if (arr[j] <= pivot)

{

i++;

swap(&arr[i], &arr[j]);

}

}

swap(&arr[i + 1], &arr[high]);

return (i + 1);

}

void quickSort(int arr[], int low, int high)

{

if (low < high)

{

int pi = partition(arr, low, high);

quickSort(arr, low, pi - 1);

quickSort(arr, pi + 1, high);

}

}

void printArray(int arr[], int size)

{

int i;

for (i=0; i < size; i++)

printf("%d ", arr[i]);

printf("n");

}

int main()

{

int arr[] = ;

int n = sizeof(arr)/sizeof(arr);

quickSort(arr, 0, n-1);

printf("The sorted array is: n");

printArray(arr, n);

return 0;

}```

Here is what the above code is Doing:
1. The quickSort() function takes last element as pivot, places the pivot element at its correct position in sorted array, and places all smaller (smaller than pivot) to left of pivot and all greater elements to right of pivot.
2. The partition() function takes last element as pivot, places the pivot element at its correct position in sorted array, and places all smaller (smaller than pivot) to left of pivot and all greater elements to right of pivot.
3. The swap() function is used to swap two elements.
4. The printArray() function is used to print the array.