Segregate 0's on Left Side & 1's on right side of the Array

Given a list of elements which only has 0's and 1's in it. We have to sort the array in such a way that 0's comes left side of the array and 1's goes right side of the array.

For example:

If the array is 
1 0 0 1 0 1 1

Then the result should be 

0 0 0 1 1 1 1

Implementation:

#include <stdio.h>
#include <stdlib.h>

/* Swap function to swap the values by reference */
void swap(int *a,int *b)
{
 int temp;
 temp=*a;
 *a=*b;
 *b=temp;
}

int main(void) {
 int *a,i,n,l,r;
 
 /* Get the number of elements of the array */
 scanf("%d",&n);
 
 /* Dynamically allocate the memory block for n integers and store the starting address of the block in a */
 a=(int*)malloc(sizeof(int)*n);
 
 /* Get the elements of the array */
 for(i=0;i<n;i++)
  scanf("%d",(a+i));
  
 /* starting index of the array in l */
 l=0;
 
 /* Ending index of the array in r */
 r=n-1;
 
 /* While start pointer is less than end pointer */
 while(l<r)
 {
  
  /* If the value in left side is 0, like where it is intended to be, we can skip to next element */
  if(*(a+l)==0)
  {
   l++;
  }
  
  /* If the value in right side is 1, like where it is intended to be, we can skip to next element from the last */
  else if(*(a+r)==1)
  {
   r--;
  }
  
  /* If both the above cases fail, 
  i.e., if we found 1 in left side and 0 in right side, swap the values
  so that 0 comes left and 1 goes right */
  else
  {
   swap((a+l),(a+r));
   
   /* Increment l value and decrement r value */
   l++;
   r--;
  }
 }
 
 /* Print the sorted array which has 0's in the left side and 1's in the right side */
 for(i=0;i<n;i++)
  printf("%d ",*(a+i));

 return 0;
}