Please answer all questions below or none at all. Thank you in advance.

6.1 We noted in Section 6.1.1 that most binary arithmetic operators are left-associative in most programming languages. In Section 6.1.4, however, we also noted that most compilers are free to evaluate the operands of a binary operator in either order. Are these statements contradictory? Why or why not?

6.2 As noted in Figure 6.1, Fortran and Pascal give unary and binary minus the same level of precedence. Is this likely to lead to nonintuitive evaluations of certain expressions? Why or why not?

6.4 Translate the following expression into postfix and prefix notation:

[-b + sqrt (b x b 4 x a x c)] / (2 x a)

Do you need a special symbol for unary negation?

6.7 Is &(&i) ever valid in C? Explain.

6.8 Languages that employ a reference model of variables also tend to employ automatic garbage collection. Is this more than a coincidence? Explain.

6.12 Describe a plausible scenario in which a programmer might wish to avoid short-circuit evaluation of a Boolean expression.

6.13 Neither Algol 60 nor Algol 68 employs short-circuit evaluation for Boolean expressions. In both languages, however, an if then else construct can be used as an expression. Show how to use ifthen else to achieve the effect ofshort-circuit evaluation.

6.16 The equivalence of for and while loops, mentioned in Example 6.64, is not precise. Give an example in which it breaks down. Hint: think about the continue statement.

6.32 Is it possible to write a tail-recursive version of the classic quicksort algorithm? Why or why not?