Assignment 3: Exception Handling

Assignment 3: Exception Handling
ECE 325 OBJECT-ORIENTED SOFWARE
DES (LEC A1 Fa18)
Assignment 3: Exception Handling
·Source code: Calculator.java
. A working copy of your solution must be submitted
to eClass before this date.
Part 1: Calculator
Your program must be able to read in the following expressions. You may wish to construct a BNF
grammar in the style of the cookie exercise as an initial task.
Compile, run, and test your program with at least these expressions:
let x = 1;
(let x = 1) + x;
(let a = 2) + 3 * a - 5;
(let x = (let y = (let z = 1))) + x + y + z;
1 + (let x = 1) + (let y = 2) + (1 + x) * (1 + y) - (let x = y) - (let y = 1) - x;
1 + (let a = (let b = 1) + b) + a + 1;
(let a = (let a = (let a = (let a = 2) + a) + a) + a) - 9;
(let x = 2) ^ (let y = 3);
(let y = 3) ^ (let x = 2);
Correct return values are 1, 2, 3, 4, 5, 6, 7, 8, and 9 respectively.
Part 2: Exception Handling
Add Java exception handling to your code by defining two exception classes SyntaxError and
RuntimeError . ·A SyntaxError exception should be thrown when an illegal character is found, a closing ) is not
found, or a = is not used in a let expression. ·A RuntimeError exception should be thrown when an identifier is encountered for which no value
can be found.
Assignment https://eclass.srv.ualberta.ca/mod/assign/view.php?id=3237745
1 of 5 2018-12-22, 9:20 p.m.
The exceptions should propagate the error to the main program which prints the diagnostics of the
error. You must handle these errors using Java exceptions and the message should be printed by an
exception handler in a catch clause.
These will be the exception test cases:
1 + (2 * 3; // syntax error: ')' expected
(let x 5) + x; // syntax error: '=' expected
(let x = 5) (let y = 6); // syntax error: operator expected
(let x = 5 let y = 6); // syntax error: ')' expected
(ler x = 5) ^ (let y = 6); // runtime error: 'ler' undefined
(let x = 5) + y; // runtime error: 'y' undefined
A Working Procedure Example
1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y)) - (let x = y) - x;
Expression Stack Pop & Return HashMap
1 1 + | 1 +| / <Empty
2 1 + (let x = 1
| let x = 1|
| 1 +|
/ x = 1
3 1 + (let x = 1) | 1 + 1|
1
(returned from
"let x = 1")
x = 1
4 1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y
| 1 + y|
| 1 + x *|
| 1 + 1 + 2 + |
/
("let y = 2"
has already
returned 2)
x = 1,
y = 2
5 1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y)
| 1 + x * 3|
| 1 + 1 + 2 +|
3
(returned from
"1 + y")
x = 1,
y = 2
6 1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y)) - (let x = y
| let x = y|
| 1 + 1 + 2 + 4 - |
/
("1 + x * 3"
has already
returned 4)
x = 2,
y = 2
7 1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y)) - (let x = y) - x | 1 + 1 + 2 + 4 - 2 - 2 |
/
("let x = y"
has already
returned 2)
x = 2,
y = 2
Assignment https://eclass.srv.ualberta.ca/mod/assign/view.php?id=3237745
2 of 5 2018-12-22, 9:20 p.m.
8 1 + (let x = 1) + (let y = 2) + (1 + x * (1 + y)) - (let x = y) - x; <Empty 4
x = 2,
y = 2
Calculator.java
Submission status
Attempt number This is attempt 1 ( 1 attempts allowed ).
Submission status Submitted for grading
Grading status Graded
Due date Thursday, 4 October 2018, 5:00 PM
Time remaining Assignment was submitted 1 hour 9 mins early
Last modified Thursday, 4 October 2018, 3:50 PM
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Grade 30.00 / 30.00
Graded on Tuesday, 9 October 2018, 12:23 PM
Assignment https://eclass.srv.ualberta.ca/mod/assign/view.php?id=3237745
3 of 5 2018-12-22, 9:20 p.m.
Graded by Aindrila Ghosh
Assignment https://eclass.srv.ualberta.ca/mod/assign/view.php?id=3237745
4 of 5 2018-12-22, 9:20 p.m.
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Assignment https://eclass.srv.ualberta.ca/mod/assign/view.php?id=3237745
5 of 5 2018-12-22, 9:20 p.m.