binary sort in an array

// CPP program to sort a binary array 
#include <iostream> 
using namespace std; 
  
void sortBinaryArray(int a[], int n) 
{ 
    int j = -1; 
    for (int i = 0; i < n; i++) { 
  
        // if number is smaller than 1 
        // then swap it with j-th number 
        if (a[i] < 1) { 
            j++; 
            swap(a[i], a[j]); 
        } 
    } 
} 
  
// Driver code 
int main() 
{ 
    int a[] = { 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 
                1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0 }; 
    int n = sizeof(a) / sizeof(a[0]); 
    sortBinaryArray(a, n); 
    for (int i = 0; i < n; i++) 
        cout << a[i] << " "; 
  
    return 0; 
}