4. Assume the following rules of associativity and precedence for expressions:

Precedence

Highest

*, /, not

+,-,&, mod

- (unary)

=,/=,<,<=,>=,>

and

or, xor

Lowest

Associativity Left to right

Show the order of evaluation of the following expressions by parenthesizing all sub expressions and placing a superscript on the right parenthesis to indicate order. For example, for the expression

a+b*c+d

the order of evaluation would be represented as

((a+(b*c)1)2 +d)3

1. a * b - 1 + c

2. a * (b - 1) / c mod d

3. (a - b) / c & (d * e / a - 3)

4. -a or c = d and e

5. a > b xor c or d <= 17

6. -a + b

5. Write a BNF description of the precedence and associativity rule defined for the expressions in Problem 4. Assume the only operands are the names a, b, c, d, and e.