Description

Important Notes:
1. The assignment is an individual project, to be finished on one’s own effort.
Marking Criterion:
1. The full score of the assignment is 100 marks.
2. Normal submission: There are two test cases (test A and test B, thereafter). A submission passes a test if and only if all 100 expressions in each test are correctly evaluated. 80 marks are given if the submission passes test A. 100 marks are given if the submission passes both test A and test B.
3. Resubmission: For normal submissions that fail in test A, a resubmission is allowed within one week after the marking. 60 marks are given if the resubmission passes test A. 75 marks are given if the resubmission passes both test A and test B.
4. Late submission: 60 marks are given if the submission passes test A. 75 marks are given if the submission passes both test A and test B. No resubmission is allowed.
5. Zero mark is given if: there is no (normal or late) submission; a normal submission fails test A and the resubmission fails test A; a normal submission fails test A and there is no resubmission; a late submission fails test A.
Running Environment:
1. The submissions will be evaluated in Java environment under Linux platform.
2. The submission is acceptable, if it runs in any of recent versions of Java SDK environment. These versions include from Java SE 8 to the most recent Java SE 17.
3. The submission is only allowed to import four packages of (java.lang.*; java.util.*; java.math.*; java.io.*) included in Java SDK. No other packages are allowed.
4. In each test, the program is required to evaluate 20 expressions within 1 second of time, with no more than 128MB memory.
5. Each student will have an opportunity to test his/her program in the evaluation platform before the submission. Detailed instructions of testing will be given around Oct. 8.
Submission Guidelines:
1. Detailed submission guideline will be given in a separate manual around Oct. 8.
2. Inconsistency with or violation from the guideline leads to marks deduction.

Functional Requirement:
1. The program evaluates the value of math expressions, and outputs an integer value or “invalid”.
2. In test A, each math expression includes (see the example below):
2.1 positive integers;
2.2 (no more than five) operators of “+” (addition), “-“ (subtraction), “*” (multiplication) and “/” (division).
3. In test A, all expressions are valid. The output is an integer value after rounding.

An example of input file for test A Expected output file:
1+2
3+4/3+7
1*2*3*4+5
2*3+4*5+6/7
1/2-1*3/3
1/2-1*4/3
… 3
11
29
27
0
-1
…

4. In test B, each math expression includes (see the example below):
4.1 numbers (integers and doubles);
4.2 (no more than ten) operators of “+” (addition), “-“ (subtraction), “*” (multiplication) and “/” (division);
4.3 (no more than three) functions including “sin” (sine function), “cos” (cosine function), “tan” (tangent function) and “sqrt” (square root function). 4.4 “(“ and “)” (brackets);
4.5 possibly blank space.

An example of input file for test B Expected output file:
1+2.0*sin(37+(25*3))
(2+ 3.50)*4*sqrt(sin(1.5))
-3+4/ (2.5+3.7)
(-3+4)/2.5+3.9
1.2-3.5*5.2-13.2
1.2-3.5*5.2-13.7
2.3*5*7 – 12*9/8
-sin(3.5-sqrt(4)) + cos(tan(2.5)) sqrt(-1)
2.5 4.0
… -1
22
-2
4
-30
-31
67 0 invalid invalid
…

Program Template:
Each submission is expected to strictly follow the template to implement the required function.

The main function is in TestMathExpr.java. In line 11 of TestMathExpr.java, an expression string is evaluated, which returns the value of the expression. Each submission is required to:
1. Modify the MathExpr.java and implement the parse() function;
2. If needed, new classes and functions can be added;
3. No modification of TestMathExpr.java is allowed.
The command used to run the program is: java TestMathExpr input.txt output.txt, where input.txt is the input file of expressions, and output.txt is the output file of values.

Appendix
1. TestMathExpr.java
2. MathExpr.java
3. inputA.txt
4. outputA.txt
5. inputB.txt
6. outputB.txt