Assignment 3 - Due Monday Oct. 21 1) problems #5, 6, 7, 9, 11b and 11d in the textbook, pages 103-105 2) Postfix expressions can be evaluated with the help of a stack data structure as follows: 1. Scan the postfix notation from left to right. a. On seeing a constant, push it onto the stack. b. On seeing a binary operator, pop two values from the top of the stack, apply the operator to the values, and push the result back onto the stack. 2. After the entire postfix notation is scanned, the value of the expression is on top of the stack. Problem: Illustrate this use of a stack to evaluate the expression 7 7 * 4 2 * 3 * -. 3) An operator is said to be "left associative" if subexpressions containing multiple occurrences of the operator are grouped from left to right. For example, if the operator "-" is left associative (which it usually is), the expression 4 - 2 - 1 is evaluated as (4-2)-1. An operator is "right associative" if subexpresssions containing multiple occurrences of the operator are grouped from right to left. The BNF grammar for a left associative operator will be left recursive while the BNF grammar for a right associative operator is right recursive. Demonstrate this by showing an example of both and explain in words why this rule is true.