Add quick sort algorithm in sorting. about algorithms HOT 1 CLOSED

#include<stdio.h>
void quicksort(int a[],int first,int last){
int i, j, pivot, temp;
if(first<last){
pivot=first;
i=first;
j=last;
while(i<j){
while(a[i]<=a[pivot]&&i<last)
i++;
while(a[j]>a[pivot])
j--;
if(i<j){
temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}
temp=a[pivot];
a[pivot]=a[j];
a[j]=temp;
quicksort(a,first,j-1);
quicksort(a,j+1,last);
}
}
int main(){
int i, n;
printf("Total elements:");
scanf("%d",&n);
int a[n];
printf("Input elements: ", n);
for(i=0;i<n;i++)
scanf("%d",&a[i]);
printf("\nUnsorted array: ");
for(i=0;i<n;i++)
printf(" %d",a[i]);
quicksort(a,0,n-1);
printf("\nSorted array: ");
for(i=0;i<n;i++)
printf(" %d",a[i]);
return 0;
}

from algorithms.