sort an array a[n] containing 0s and 1s with time complexity n and you cant use more than 1 data structure

//      TIME: O(n)  ||   Space : O(1)


#include<stdio.h>
int main()
{
    int A[20],i,j,n,temp;
    printf("Enter n :");
    scanf("%d",&n);
    for(i=0;i<n;i++)
        scanf("%d",&A[i]);
    printf("\n--");
    i=0;
    j=n-1;
    while(i<j)
    {
        while(A[i]==0)
            i++;
        while(A[j]==1)
            j--;
        if(i<j)
        {
            temp=A[i];
            A[i]=A[j];
            A[j]=temp;
            i++; j--;
        }
    }// end of while
    printf("\n");
    for(i=0;i<n;i++)
        printf("%d ",A[i]);
    printf("\n");
return 0;
}