quicksort.c

#include <stdio.h>
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);    
 
    int j;
    for (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 pivot = partition(arr, low, high);

        quicksort(arr, low, pivot - 1);
        quicksort(arr, pivot + 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[] = {12, 11, 13, 5, 6, 7};
    int n = sizeof(arr) / sizeof(arr[0]);

    printf("Original array: \n");
    printArray(arr, n);

    quicksort(arr, 0, n - 1);

    printf("Sorted array: \n");
    printArray(arr, n);

    return 0;
}