Quick Sort program in C

quick_sort.c

// Refer to these video tutorials : 
// https://www.youtube.com/watch?v=MZaf_9IZCrc  
// and
// https://www.youtube.com/watch?v=T3Paafdqcsw

#include <stdio.h>

void quick(int a[], int first, int last){
  if(first<last){
    int temp;
    int i = first;
    int j = last;
    int pivot = first;
    while(i<j){
      while(a[i] <= a[pivot]){
        i++;
      }
      while(a[j] > a[pivot]){
        j--;
      }
      if(i<j){
        temp = a[i];
        a[i] = a[j];
        a[j] = temp;
      }
    }
    temp = a[j];
    a[j] = a[pivot];
    a[pivot] = temp;
    quick(a,first,j-1);
    quick(a,j+1,last);
  }
}

int main(){
  int n, a[100];
  printf("Enter size: \n");
  scanf("%d",&n);
  printf("Enter %d elements : \n",n);
  for(int i=0;i<n;i++){
    scanf("%d",&a[i]);
  }
  quick(a,0,n-1);
  printf("Sorted array : ");
  for(int i=0;i<n;i++){
    printf("%d ",a[i]);
  }

  return 0;
}