Software Development

Program Development Cycle

• Analyze Problem: Define problem, record program specifications and recognize inputs, process, output and UI.
• Design Program: Develop a logic plan, write algorithm using pseudocode or flowchart and test solution
• Code Program: translate algorithm into high-level language with comments/ remarks and produce user interface with executable processes.
• Test and Debug Program: Test programs using test data, find and correct any errors and make sure the results are correct.
• Formalize Solution: Review program code, revise internal documentation and create end-user documentation.
• Maintain Program: Provide education and support to end-user, correct any bugs and modify if user requests.

Integrated Development Environment

• A software application that allows the creation of a program.
• Contains a source code editor, build automation tools, a debugger.
• Coding:
• Reserved words are used by it as command prompts
• Listed in the end-user documentation of IDE
• A series of files consisting of pre-programmed subroutines, may also be provided by the IDE.
• Initial Error Detection:
• The IDE executes the code and initial error detection carried out by compiler/interpreter.
• Debugging:
• Single stepping: goes through each line of code and steps into procedures. Allows you to see the effect of each statement on variables.
• Breakpoints: sets within code; program stops temporarily to see if it is operating alright up to that point.
• Variable dumps (report window): variable values are shown at specific parts of program.

Features found in a typical IDE

• Prettyprinting: The presentation of the program code typed into an editor. This includes indentation, colour-coding of keywords and comments.
• Context-sensitive prompts: Displays hints or a choice of keywords and available identifiers appropiate at the current insertion point of the program code.
• Dynamic syntax checks: When a line has been typed, some editors perform syntax checks and alert the programmer to errors.
• Expanding and collapsing code blocks: Statements, in programs with many lines of code, can be collapse, to prevent excessive scrolling.

Types of errors

• Syntax errors:
• When source code does not obey the rules of the language.
• Compiler generates error message.
• Run-time errors:
• Source code complies to machine code but fails upon execution.
• When the program keeps running you have to close it manually.
• Logic errors:
• Program works but give incorrect output.

Testing strategies

• Black-box testing:
• Use test data for which result have already been calculated and compare result from program with expected result.
• Testing only considers input and output and the code is viewed as being in a 'black-box'
• White-box testing:
• Examine each line of code for correct logic and accuracy.
• May record value of variables after each line of code.
• Every possible condition must be tested.
• Stub testing:
• Stubs are computer programs that acts as a temporary replacement for a called module and give the same output as the actual program or software.