sort array of 0,1 and 2

#include <bits/stdc++.h> 
using namespace std; 

void sort012(int a[], int arr_size) 
{ 
	int lo = 0; 
	int hi = arr_size - 1; 
	int mid = 0; 

	// Iterate till all the elements 
	// are sorted 
	while (mid <= hi) { 
		switch (a[mid]) { 

		// If the element is 0 
		case 0: 
			swap(a[lo++], a[mid++]); 
			break; 

		// If the element is 1 . 
		case 1: 
			mid++; 
			break; 

		// If the element is 2 
		case 2: 
			swap(a[mid], a[hi--]); 
			break; 
		} 
	} 
} 

// Function to print array arr[] 
void printArray(int arr[], int arr_size) 
{ 
	// Iterate and print every element 
	for (int i = 0; i < arr_size; i++) 
		cout << arr[i] << " "; 
} 

int main() 
{ 
	int arr[] = { 0, 1, 1, 0, 1, 2, 1, 2, 0, 0, 0, 1 }; 
	int n = sizeof(arr) / sizeof(arr[0]); 

	sort012(arr, n); 

	cout << "array after segregation "; 

	printArray(arr, n); 

	return 0; 
}