ENGR/CS 101 CS Session
Lecture 2
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Tuesday, October 22, is the Annual CECS
"Kegger", 5-7pm, Hale basketball courts
Starting with the next class, we will be using
Visual Studio C#. If you would like to have a
copy for your own computer:
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Lecture 2
All students in EECS classes are enrolled in the
UE MS Alliance program. Email with instructions
should have been sent at beginning of term. Full
Visual Studio 2012 is available. (Windows 8, too.)
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Outline
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Software life cycle
Project 1: Dot Chaser Game
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Software Life Cycle
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Specification of the problem/task
Analysis and design of a solution
Implementation of the solution
Testing and debugging
Maintenance and evolution of the system
Obsolescence
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Specifications
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How does the user interact with the program?
What are the results of the computation?
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Analysis and Design
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How will the program accomplish the
specifications?
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Identify the data being used
Identify the algorithm that will compute the result
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Implementation
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Use a programming language to implement
the program.
Syntax: What are the legal "sentences" in the
language? Semantics: What do the
"sentences" mean?
Compilers and interpreters enforce syntax.
Semantics determine whether the
computation is correct.
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Compiling vs. Interpreting
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Some languages are compiled with a
program called a compiler. Source code file
is translated into a machine code file.
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Examples: C/C++, Java, Pascal, COBOL, Fortran
Other languages are interpreted. An
interpreter is a program that receives
programming language statements and
executes them directly.
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Examples: (original) BASIC, LISP, Prolog, LOGO
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Testing and Debugging
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Testing should try to cover all possible ways
a user might interact with a program
A bug is a logic error that causes an incorrect
result.
Debugging is the process of finding and
correcting bugs.
A debugger is a program that displays the
internals of a program as it runs to aid in
debugging.
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Maintenance/Obsolescence
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It is estimated that 80% of the cost of a
software product is expended after the first
release.
Maintenance includes fixing bugs, adapting to
changing environments, increasing
functionality
Obsolescence is handling the transition when
a software product will no longer be available
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Project 1:
Dot Chaser Game
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A game is specified by
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User interactions
Rules of the game
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User interactions
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Game starts with a randomly placed dot.
When the user clicks on the dot, it moves to
another random place in the game area.
Otherwise, the dot is to move periodically to
another random place in the game area.
User must be able to start and stop the
game.
User must be able to reset the game.
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Graphical User Interface (GUI)
Design
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Form – main application window
Panel – container that is a subarea of a
window
Button – control with default action of mouse
click
Label – area of text, good for displaying
results
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GUI Mockup
Form
Labels
Buttons
Panel
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Game Rules
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Basic rule: when a user clicks on the dot, her
score increases by 1.
Some other ideas?
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Analysis and Design
Program = Data + Algorithm
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Data is the information needed to do the
computation.
What data do we need for this game?
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Lecture 2
the score, an integer with initial value of 0
…
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Algorithm
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Algorithm: a series of well-defined steps that
can be followed as a procedure.
Example: Move the dot
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Compute new x and y coordinates
Set the x and y coordinates of the dot
Example: Update the score
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Compute new numeric score
Update user interface score
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Algorithm
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More complex algorithm: Handle a dot click
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Update the score
Move the dot
Reset the timer
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Implementation
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We will use the C# language.
Start with implementing the GUI next time
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