How would you sort an array that consists of only zeros and ones in only one pass? Make two points p1 and p2 pointing to the first element,

How would you sort an array that consists of only zeros and ones in only one pass?
Make two points p1 and p2 pointing to the first element,

foo(int*a, int len)
{
int* p1=a;
int* p2=a[len-1];
while(p1!=p2)
{
if(*p1==0&&*p2==1)
{p1++;p2--;}
eles if(*p1==0&&*p2==0)
{p1++;}
else if(*p1==1&&*p2==0)
{*p1=0;*p2=1;p1++;p2--;}
else//1 1
{p2--;}
}
}