Assignment 1 – Spring 2018 Page 1 out of 4
Faculty of Engineering and Information Technology
School of Software
31927 – Applications Development with .NET
32998 – .NET Applications Development
SPRING 2018
ASSIGNMENT 1 SPECIFICATION
DUE DATE – Monday, 17th September 2018
This assignment is worth 25% of the total marks
Requirement Assignment Documentations
This assignment is split into two documents.
1. Assignment Specification. This document contains the specification for what
you will be required to do.
2. Assignment Addendum. This document contains all other details regarding
the assignment, including assignment submission and the assessment
scheme.
Requirement
In this assignment you are to prepare a C# program that will act as a simple
equation solver. The equation solver will be run from the command line and will only
work with integer numbers, a single variable (X) and the following arithmetic
operators: + – * / % ^2. The % operator is the modulus operator, not the percentage.
^2 is the square of a number/variable (e.g. X^2 = X2)
For example, if the C# program is compiled to Equ.exe, the following demonstrates
how it will appear in the command line:
calc 3X + 5 = 8
X = 1
In the command line, the argument is entered as the “calc” keyword followed by a
space and followed by a sequence of numbers, variables, and operators, such as:
calc
Hitting the enter key will cause the program to evaluate the arguments and print the
result as one or more numbers separated by “,”:
X=
The console should remain open and allow the user to continue to enter equations to
be solved.
Assignment 1 – Spring 2018 Page 2 out of 4
The program must follow the math rules of solving equations with 1 variable type (i.e.
linear and quadric style equations). For example:
2X – 1 = 0
3X + 8X = 33
4X – 7 = 8X – 5
X / (x+12) = 1 / 13
X^2 + X^2 + 4X + 9X + X = 10 + 1 * 2 % 4
The program must follow the usual laws of arithmetic which says:
1. The * / and % operators must all be evaluated before the + and –
operators.
2. Operators must be evaluated from left to right.
For example, using Rule 1
X = 2 + 4 * 3 – 6
Becomes
X = 2 + 12 – 6
Which results in
X = 8
X^2 + 2X^2 = 27
Becomes
3X^2 = 27
Which results in X = 3
X^2 – 4 = 11 * 7
Becomes
X^2 – 4 = 77
Becomes
X^2 = 81
Which results in X = 9
If we did not use Rule 1 then 2+4*3–6 would become 6*3–6 and then 18–6 and
finally 12. This is an incorrect result.
If we do not use Rule 2 then the following illustrates how it can go wrong
4*5%2
Going from left to right we evaluate the * first, which reduces the expression to 20%2
which becomes 0. If we evaluated the % first then the expression would reduce to
4*1 which becomes 1. This is an incorrect result. Remember, we are using integer
mathematics when doing our calculations, so we get integer results when doing
division. For example:
calc X = 20 / 4
X = 5
Also note that we can use the unary + and – operators. For example:
calc X = -5 / +2
Assignment 1 – Spring 2018 Page 3 out of 4
X = -2
Your program must also check to make sure the command line argument is correct
and handle the equation parts. If not your program must generate an appropriate
error message and then terminate. For example:
calc X = – 3 + 4 / 6 (spaces represent splitters between numbers and operators)
Becomes X = -3 + 4 / 6
calc X = 3 + 4 / 6 + (space after+)
Becomes X = 3 + 4 / 6 + 0 (replace by 0)
Becomes X = 3 + 4 / 6
calc X = 3 + + + 4 – 6 (operation elimination)
Becomes X = 3 + 4 – 6
calc X = 3 – – – 8X – 4
Becomes X = 3 – 8X – 4
calc X + 3 + 6 + 3333333333333
Invalid Input (this is not equation and invalid as well)
calc X^2 = 2121212121 + 2020202020
Out of Integer Range
calc X = 4 % 0
calc X = 4 / 0
Division by zero
Program Hints
1. Getting your program to solve expressions that only use the + and –
operators is fairly easy. I would suggest you get your program working at this
level before attempting to get it to work with the other operators.
2. You will find this problem much easier to solve if you application has a good
design concept; create a generic input that takes all parameters and
operations and break it down into smaller methods responsible for
validations, aggregations and calculations. For example, enumerate the
possible operations and then have a method that solves (number operator
number). Also have a method that gets the number from a string and another
that gets the operator from a string. Also note that splitting your code up will
give you a better design mark.
Assignment 1 – Spring 2018 Page 4 out of 4
Assignment Objectives
The purpose of this assignment is to demonstrate competence in the following
skills.
Problem solution
Employ basic mathematic skills to develop C# program
Program design
Array and string manipulation
Command line arguments
Creating Object Oriented methods in C#
These tasks reflect all the subject objectives.
The solution of this assignment will take between 200 and 300 lines of code,
including white space (blank lines) comments, etc. The exact number will
depend on how the students solve the task. As part of your subject workload
assessment, it is estimated this assignment will take more than 30 hours to
complete.