Program Development
C# Programming
January 30, 2007
Professor J. Sciame
Computer Aided Problem
Solving
• Steps for Computer Aided Problem Solving:
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Program Analysis and Specification
Algorithm Development
Program Coding
Program Execution and Testing
Program Maintenance
Program Analysis &
Specification
• Determine:
– Program Input
– Program Output
• Specification = Input & Output
• Problems Encountered
– Changing Values
– Being too specific
Algorithm Development
• Algorithm = The formulation of a problem
as a detailed sequence of simple steps.
• Algorithms are designed using three basic
methods of control:
– Sequential Control
– Selection Control
– Repetitive Control
Pseudocode
• Pseudocode is a mixture natural language
and symbols, which include:
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Mathematical Operators
Variable Names
Comments
Keywords
Indentation
Flowchart
• A graphical display of an algorithm.
• Uses:
– Symbols
– Flow lines
• Alternate - Top Down Design
Program Coding
• To express the algorithm in a programming
language
• Concepts:
– Syntax
– Variables
– Data Types
• Readability
Program Execution
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Write the program with the editor
Include preprocessor codes
Save and compile the program
Link the program
Load into memory
Execute (Run)
Errors
• Syntax (or Compile Time)
• Run Time
• Logic
Program Maintenance
• Responsibilities:
– Testing & Validation
– Maintenance
Software Engineering
• The study of the use of the techniques used
to solve problems
• Systems Analysts - Help in complex
problems
Memory Concepts
• Variable names correspond to locations in
memory
• All variables have:
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a name
a type
a size
a value
Memory Concepts II
• The statement cin >> integer1 or x = a + b
is called a destructive read-in.
• The statement cout << x is called a nondestructive read-out
Arithmetic Operators
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Addition +
Subtraction Multiplication *
Division /
Modulus %
Order of Operations
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Parentheses must be cleared.
Exponentiation
Multiplication or Division (left to right)
Addition or Subtraction (left to right)
In nested parentheses, the innermost
parentheses are first, working out to the
outermost set.
Equality and Relational
Operators
• Equality
– (x is equal to y) x = = y
– (x is not equal to y) x != y
• Relational
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(x is greater than y) x > y
(x is less than y) x < y
(x is greater than or equal to y) x > = y
(x is less than or equal to y) x < = y