Dont use this practice in your lifetime

Question

Using ++ and -- in single expression for same variable is to be strictly avoided. Although it is less possible to predict the output of such expressions, it should be avoided by any programmer, irrespective of the language. It will cause an Undefined Behaviour.
a = 3; b = 2;
x = ++a - --a + (b* ++a);
While the usage of this expression wont cause any Compilation or System error, because it is syntactically correct, it will surely cause
Logical errors, giving different results in different OS, compiler.

Answer 1

a++ is STRONGLY RECOMENDED instead of
a += 1;
or
a = a + 1;

Answer 2

well they are complicated but they are executed fastly than the normal expression.