CS 211. Project 5 Infix Expression Evaluation

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Lambert Wiggins
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1 CS 211 Project 5 Infix Expression Evaluation

2 Part 1 Create you own Stack Class Need two stacks one stack of integers for the operands one stack of characters for the operators Do we need 2 Stack Classes? (perhaps not) one Stack Class of the Token class from the proj5base.cpp file will work one Stack Class of integers will also work since characters are a sub-type of integers (conversion with type cast may be needed) Use C++ templating is not allowed!! First: An INSANE idea for your first C++ Object program Second: You are to write this code yourself not copy it from the internet

3 Part 1 Create your own Stack Class Requires implementation with a Dynamic Array Data Members: pointer to a dynamic array amount of space currently allocated amount of space currently in use Methods Constructor/Initialize Reset (clear array) IsEmpty() Push() Pop() Top()

4 Part 1 Create your own Stack Class Naming your class MyStack rather than Stack is suggested avoids confusion with any system provided stack class Dynamic array initialize to only hold 2 values grow by an increase of 2 values each time just like Project 2 Data Members MUST be private In-Class Use Only Methods should also be private ex: grow() method called by push()

5 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN If token is Value: Push on If token is Operator: Follow Algorithm Current Token:

6 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: VALUE 3

7 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: VALUE 3 Push on 3

8 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR * 3

9 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR * Since is Empty Push on OP Stack 3 *

10 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: VALUE 4 3 *

11 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: VALUE 4 Push on VALUE Stack 4 3 *

12 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR *

13 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR + Since Top OP has higher precedence PopAndEval( ) then 4 3 *

14 PopAndEval ( ) Result = Val1 Op Val2 4 3 *

15 PopAndEval ( ) Result = Val1 * Val2 Step 1: Op = Top of OP Stack 4 3 *

16 PopAndEval ( ) Result = Val1 * Val2 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack 4 3

17 PopAndEval ( ) Result = Val1 * 4 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of 4 3

18 PopAndEval ( ) Result = Val1 * 4 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop 3

19 PopAndEval ( ) Result = 3 * 4 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of 3

20 PopAndEval ( ) Result = 3 * 4 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of Step 6: Pop

21 PopAndEval ( ) Result = 12 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of Step 6: Pop Step 7: Evaluate Result

22 PopAndEval ( ) Result = 12 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of Step 6: Pop Step 7: Evaluate Result Step 8: Push Result on 12

23 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR + Since Top OP has higher precedence PopAndEval( ) then 12

24 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: OPERATOR + Since Top OP has higher precedence PopAndEval( ) then Push on OP Stack 12 +

25 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: Value 5 Push on

26 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: EOLN PopAndEval( ) until OP Stack is Empty

27 PopAndEval ( ) Result = Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of Step 6: Pop Step 7: Evaluate Result Step 8: Push Result on

28 PopAndEval ( ) Result = = 17 Step 1: Op = Top of OP Stack Step 2: Pop OP Stack Step 3: Val2 = Top of Step 4: Pop Step 5: Val1 = Top of Step 6: Pop Step 7: Evaluate Result Step 8: Push Result on 17

29 Step 1. Create/Clear and Operator Stack Step 2. Get Tokens until End Of Line is Reached 3 * EOLN ^ If token is Value: Push on If token is Operator: Follow Algorithm Current Token: EOLN When OP Stack is Empty Expression Result on Top of 17

CS 211 Programming Practicum Spring 2018

CS 211 Programming Practicum Spring 2018 Due: Thursday, 4/5/18 at 11:59 pm Infix Expression Evaluator Programming Project 5 For this lab, write a C++ program that will evaluate an infix expression. The algorithm REQUIRED for this program will