Assignment •  FAQ •  Development Guide •  Code •  Checklist •

HW4 Assignment

What to do?

You must turn in your program by Wednesday, October 20th, 2021 at 11:59am (NOON).
In this assignment, you will be developing a program that simulates a top-of-the-line calculator which performs advanced commands such as addition, subtractions, multiplication, division, exponentiation, and factorial! The program will accept mathematical expressions in "infix" notation such as...

( ( 27 + 452 ) * 2 - 16 ^ 2 ) / 7

convert it to its "postfix" equivalent expression...

27 452 + 2 * 16 2 ^ - 7 /

and then evaluate the "postfix" expression.
Note: All operations are integer operations. Don't worry about negative input.

The methods to write in Calc.java:

long eval (LongStack stack1);
long intopost (LongStack stack1);

static long exponent (long power, long base);
static long fact (long xxx, long ignored);
static long setupword (char character);

The files you need to copy over from your hw3:

LongStack.java

• Once you copy over your LongStack.java file, navigate to the writeStack method inside LongStackEngine.
• Change the casting from char to byte
  • From: (char) (stack[index])))
  • To: (byte) (stack[index])))
• You'll need to add debug messages later inside your push, pop and top methods to display hexadecimal output when a negative number is on the stack.

You do not need to write any debug statements in the Calc.java file, but when you run ./Calc -x, you will see the debug statements you originally wrote in LongStack.java to track allocating, jettisoning, and internal operations.

Function Descriptions

eval:

Utilizing 2 Stacks, evaluate mathematical expressions from "postfix" notation. Refer to the Calc.java.empty for the algorithm.

intopost:

Utilizing 2 Stacks, convert "infix" mathematical expressions entered by the user into their "postfix" equivalents. Refer to the Calc.java.empty for the algorithm.
Hint: You will need to use MyLib.getchar() to read input and then push it to your stacks. It has similar functionality to fgetc, which you implemented in hw1.
Another hint:You will also use MyLib.ungetc() to put a character back to the input stream.

exponent: /* called from eval */

Raising base to the power exponent.

fact: /* called from eval */

Calculating xxx factorial.

setupword: /* called from intopost */

Constructor funtion for longs representing operators to be stored on your LongStack objects. The representation for the operators should have everything associated with that operator:

• A distinction from numbers
• The index in the methods array corresponding to that operator
• The priority of that operator
• The ASCII code

Grading breakdown

Commenting/Documentation:

20%

Correctness/Execution:

60%

Style:

20%

How to get started?

Copy and past the following commands into your terminal

cd
cd ../public/hw4
make install
cd
cd hw4/java
cp ~/hw3/java/LongStack.java LongStack.java
mv Calc.java.empty Calc.java
ls

 

Assignment •  FAQ •  Development Guide •  Code •  Checklist •