Chapter 20.11, Problem 20.11.2CP

Program Plan Intro

In the EvaluateExpression program, the problem can be solved with help of two stacks such as operandStack and operatorStack.

Algorithm contains two phases. They are,

Phase 1:

Initially, the program starts the scanning the given expression from left to right to extract the operands, operators, and parentheses.

• If the extracted element is operands, then push those operands into operandStack stack.
• If the extracted element is operator such as “+” or “-”.
  • Process each and every operator at top of stack and then push it into operatorStack stack.
• If the extracted element is operator such as “*” or “/”.
  • Process “*” or “/” operator at top of stack and then push it into operatorStack stack.
• If the extracted element is symbol such as “(”.
  • Process “(” symbol at top of stack and then push it into operatorStack stack.
• If the extracted element is symbol such as “)”.
  • Process “)” symbol at top of stack and then push it into operatorStack stack. Repeatedly process the operators until “(” symbol.

Phase 2:

• Clear the stack from the top of operatorStack until empty the operatorStack.