Reverse polish notation in C

CSCI 281 LAB 5 - STACKS AND A

CALCULATOR

ASSIG NM ENT

Using 2 stacks to implement a calculator.

C A L C U L A T O R

1. User input of two types. Integer values and associated tokens (*, /, -, +)

2. As the user needs to enter the input in the following manner:

3 + 5 / 17 – 3 * 9 + 2 * 8 + 7

3. You should use a looping scanf to allow the user to enter digit, then a char, then a digit,

then a car etc until they press the enter key.

4. Each integer (evens) will be added to the integer stack.

5. Each token (odds) will be added to the character stack.

(Hint: counter%2 = 0 if even, counter%2 = 1 if odd.)

Example of full stacks:

6. After the stacks are full or the user is done entering numbers and tokens, complete the

following:

a. You will read the first number off the stack, then the first char, then the second

number.

b. You will need to use a switch statement to determine which token you have, and

then complete the operation. In the example above, you have a +, so you will set a

double variable called calculation equal to 7 + 8.

c. Next you will remove the next number from the number stack and the next token

from the char stack. You will complete the next operation ( * in this case) by

setting calculation equal to calculation * 2.

d. And so on for the rest of the stacks contents.

e. 3 + 5 / 17 – 3 * 9 + 2 * 8 + 7 will result in a value of -17.

f. See the following walkthrough:

Calculation = 8 + 7 = 15.000000

Calculation = 15 * 2 = 30.000000

Calculation = 30 + 9 = 39.000000

Calculation = 39 * 3 = 117.000000

Calculation = 17 - 117 = -100.000000

Calculation = -100 / 5 = -20.000000

Calculation = -20 + 3 = -17.000000

E R R O R C H E C K I N G

1. You only have 4 tokens, so make sure the user does not enter the wrong token. Tell them

to re-enter the entire thing again if they enter either an incorrect token, or they enter

2. If the user is done entering numbers and tokens and total number of numbers - total

number of tokens is not equal to 1, then their input is incorrect.

a. You need one more number than token for this to work.

3. Make sure the user is alternating numbers and tokens. If they try to enter 7 8 or * - they

are incorrect and you need to have them re-enter their information.

S E T U P S TE P S :

1. Create a new project. Do not name your main file main.c. Be descriptive and use your

last name. No spaces. Use camel case or underscores.

2. Delete all the code in the new main file.

3. Copy the stack code from your Stack project we made in class on Friday 3/22 into the

file.

4. Run it to make sure it works. See slides for expected output.

5. Remove the code in the main except the return exit success.

6. Change #define MAXSIZE 8 to two macros instead.

7. You need 2 top pointers. topInt and topChar too keep track of the top of each stack

since they are not the same.

8. Modify your functions as follows:

a. isEmpty, isFull, size – should not pass a struct, should pass an integer flag value.

The flag will be 0 if you are checking the integer stack and 1 if you are checking the

char stack.

b. Peek, push, pop – should make two of each of these functions. One for integers

and one for character tokens. The integer versions of the functions should deal with

integer values only. The char versions of the functions should deal with characters

only.

c. PrintStack – Modify the entire function to only print the values in the two stacks,

DO NOT REMOVE THE STACK ITEMS!! You will need a loop to iterate over

the arrays and print their values. MAKE SURE YOU INDICATE WHICH STACK

YOU ARE PRINTING IN THE OUTPUT.

9. Add code to produce the calculated values as shown above using the steps in the

calculator section. The user can enter any of the 4 tokens and any integer value. When

they are done with input they press enter.

10. Include all perinate error messages.

11. Output calculation at each step and then show the final result.

GRAD ING RUBRI C

Assignment Grading

Functional code – no errors present. If code does not run, then no points will be awarded. The grade of 0 will be given.

Cheating – If your code is identical to another students, both students will receive a grade of 0 for the assignment.

Grade Item Percent of Grade

Looping Input – let user choose one of two options, must use a switch statement.

10pts

Changes made to functions as specified in the instructions. 10pts

Error checking present as specified. 20pts

Calculation result reached using the above steps correctly. Correct calculator result.

50pts

Correct format for user input and code output 10pts

Deductions Points Deducted

Naming your main c file main.c. It has to be descriptive. -10pts

Not using a switch statement. -10pts

Not modifying the functions as specified. -20pts for each function

Incorrect int/char usage -5pts for each infraction

Using global variables for anything except top and the structure. -30pts per variable

Passing all addresses/variables into every function even if they are not needed in the function.

-30pts per function

1 character variable names, even in loops -5pts per variable

Uneven tabbing -31pts

Unreadable code (either through tabbing, spacing, variables names etc) -31pts

No/few comments/copied comments -31pts