sir,
result for cout<<b is 8 in both the cases. i had written cout<<b<<a; just to see what value 'a' is holding.
problem is with b=a+a++ +a++ +a++; is giving output 8 when a=1 and second part b=a+a+a++ +a++ +a++ is giving output 8. in the second statement there is five a whree as in first only four.