Pre and Post Increments

We cannot use pre and post in a single statement because it is compiler dependent program....
like 

int a =10;

cout<<++a + a++ + a++;

It is absolutely compiler dependent program..

int A=900, B=100; A++; cout<<A<<endl; ++B; cout<<B<<endl;	int A=900, B=100; A+=B++; cout<<A<<B<<endl; A+=++B; cout<<A<<B<<endl;
900 101	1000101 1102102