Chapter 13.5, Problem 17SC

Program Plan Intro

Expression:

• An expression is a sequence of terms separated by “+” or “-”.
• Every term can be broken to sequence of factors separated by “*” or “/”.
• Every factor is either a number or a parenthesized expression.
• The syntax tree or parser tree decides which operations should carry out first.

Mutually Recursive Method to solve an expression:

• A mechanism in which a set of cooperating methods calls each other is known as mutual recursion.
• To compute the value of expression, 3 mutually recursive methods are used. They are,
  • “getExpressionValue”
  • “getTermValue”
  • “getFactorValue”
• The method “getExpressionValue” calls the method “getTermValue” to get the term value.
• The method “getTermValue” calls the method “getFactorValue” to get the value of factors.