CSCI 0299: C++ for Engineers - Lecture 1 Preliminaries Flashcards

Software Engineering and Software Development Life Cycle

• Computer Program (Software): A self-contained set of instructions used to operate a computer to produce a specific result. It is a solution developed to solve a particular problem, written in a form that can be executed on a computer.

• Software Development Procedure: A systematic process that helps developers thoroughly understand the problem to be solved and construct an effective, appropriate software solution.

• Software Engineering: A discipline focused on creating readable, efficient, reliable, and maintainable software programs and systems. It utilizes the software development procedure to accomplish these operational goals.

• Three Phases of Program Development:

  • Phase I: Development and Design

  • Phase II: Documentation

  • Phase III: Maintenance

Phase I: Development and Design

• Program Requirement: A formal request for a program or an explicit statement describing a problem. The receipt of a program requirement triggers the start of Phase I.

• Step 1: Analyze the Problem:

  • Determine and understand the exact output items the program must produce.

  • Determine the required input items.

  • Together, these inputs and outputs are referred to as the problem's Input/Output (I/O).

• Step 2: Develop a Solution:

  • Select the exact sequence of steps, termed an algorithm, to solve the problem.

  • Refine the algorithm iteratively, beginning with the initial solution outlined in the analysis step until an acceptable and complete solution is defined.

  • Thoroughly check the proposed solution for functional correctness.

  • Structure Diagrams:

  • First-Level Structure Diagram: Illustrates top-level functional modules (e.g., high-level components of an inventory tracking system).

  • Second-Level Structure Diagram: Illustrates further refinements and detailed sub-components of the initial top-level modules.

• Step 3: Code the Solution:

  • Involves writing the actual C++ program code corresponding directly to the algorithm designed in Step 2.

  • Software implementations must incorporate well-defined patterns or control structures:

  • Sequence: Specifies the precise order in which instructions are executed.

  • Selection: Enables branching between different execution paths based on the evaluation of a condition.

  • Iteration: Allows the repetition of identical operations or instruction blocks based on a condition (commonly called looping or repetition).

  • Invocation: Involves invoking or calling a designated set of statements whenever needed.

• Step 4: Test and Correct the Program:

  • Testing: A structured methodology used to verify program correctness and confirm that all initial requirements are satisfied.

  • Bug: Any error or flaw in a computer program.

  • Debugging: The multi-step process of locating an error, applying a correction, and verifying that the correction resolves the issue without introducing new errors.

  • Testing Guarantee: Testing can demonstrate the presence of bugs, but it can never guarantee the absolute absence of errors.

  • Effort Allocation: In large commercial projects, software design and development steps require significant time and effort, with major portions allocated to upfront analysis, structural design, systematic coding, and rigorous testing.

Phase II: Documentation

• Documentation Artifacts: Every completed problem solution must include five primary, distinct documents:

  1. Program description

  2. Algorithm development and record of changes

  3. Well-commented program listing

  4. Sample test runs

  5. Users' manual

Phase III: Maintenance and Backup Procedures

• Phase III: Maintenance:

  • Encompasses ongoing correction of newly discovered bugs over time.

  • Includes code revisions made to accommodate changing user requirements.

  • Involves adding new features and updated operational functionalities.

  • Maintenance is typically the longest phase in the software life cycle and often serves as a primary source of recurring revenue for software companies.

  • Well-written code and comprehensive Phase II documentation are vital for effective maintenance.

• Backup Procedures:

  • The operational practice of creating exact duplicate copies of program source code and documentation on a regular schedule.

  • Serves as insurance against data loss or system failure.

  • Storing backup copies at off-site locations provides additional protection against physical disaster.

Algorithms and Flowcharts

• Algorithm: A step-by-step sequence of instructions detailing how data is to be processed to generate a desired output. An algorithm must terminate.

• Representation Formats for Algorithms:

  • Pseudocode: English-like descriptive phrases used to outline steps in an algorithm.

  • Formula: Mathematical equations representing processing logic.

  • Flowchart: Graphical diagrams using standardized geometric symbols connected by directional lines.

• Sample Problem: Calculate the sum of all whole numbers from $1$ through $100$.

• Standard Flowchart Symbols:

  • Terminal: Oval shape indicating the start or end point of a program.

  • Input/Output: Parallelogram indicating reading inputs or writing outputs.

  • Process: Rectangle indicating arithmetic computations or data manipulation.

  • Flow Lines: Arrows connecting flowchart symbols that specify logic execution order.

  • Decision: Diamond shape specifying a conditional evaluation point where the execution path branches.

  • Loop: Symbol specifying the initial, limit, and increment values of an iterative loop construct.

  • Predefined Process: Symbol specifying execution of a predefined module or function call.

  • Connector: Symbol indicating entry to or exit from another section of the flowchart.

  • Report: Symbol specifying a written or printed output report.

• Example Flowchart Execution (Average of Three Numbers):

  • Step 1: Start (Terminal symbol)

  • Step 2: Input three values (Input/Output symbol)

  • Step 3: Calculate the average (Process symbol)

  • Step 4: Display the average (Input/Output symbol)

  • Step 5: End (Terminal symbol)

Software Classifications and Programming Languages

• Programming: The process of creating software instructions.

• Programming Language: A defined syntax and instruction set used to build computer programs.

• Machine Language:

  • The only language that a computer can natively execute.

  • Also referred to as executable programs or executables.

  • Composed entirely of sequences of binary numbers ($0$s and $1$s).

  • Machine instructions consist of two parts: an instruction code (opcode) and an address.

• Assembly Language:

  • Replaces binary opcodes with word-like symbolic mnemonics such as ADD, SUB, and MUL.

  • Uses decimal numbers and readable labels for memory addresses (e.g., ADD 1, 2).

  • Requires translation into machine code via an Assembler.

• Language Abstraction Levels:

  • Low-Level Languages: Languages whose instructions are tied directly to one specific type of computer hardware (e.g., machine language, assembly language).

  • High-Level Languages: Instructions resemble written natural languages like English and can be executed across diverse hardware platforms (e.g., Visual Basic, C, C++, Java).

• Source Code Translation:

  • Source Code: Program code written in high-level or low-level human-readable languages.

  • Interpreter: Translates source code one statement at a time, executing each instruction immediately after translation.

  • Compiler: Translates all program statements at once into an executable program (object program) that is stored for execution at a later time.

  • C++ is predominantly a compiled language.

• Programming Paradigms:

  • Procedural: Code is structured into modular, self-contained instruction blocks called procedures or functions (e.g., FORTRAN, ALGOL, COBOL, BASIC, Pascal, C).

  • Object-Oriented: Code organizes software around reusable units called objects that combine data and function methods.

  • C++ contains features of both procedural and object-oriented programming.

• Software Types:

  • Application Software: Programs designed to carry out specific end-user tasks.

  • System Software: The set of control programs operating computer hardware.

  • Booting: Loading system software into primary memory upon system start up.

  • Bootstrap Loader: A permanent, automatically executed system component that initiates the boot sequence.

  • Operating System (OS): The comprehensive suite of system programs managing:

  • Memory allocation

  • CPU time scheduling

  • Input and output device control

  • Secondary storage device management

  • Multi-User System: Supports simultaneous program execution by multiple users.

  • Multitasking System (Multiprogrammed System): Supports simultaneous execution of multiple programs for a single user.

Computer Hardware and Storage

• Hardware Components:

  • Arithmetic and Logic Unit (ALU): Performs all arithmetic calculations and logical comparisons.

  • Control Unit: Monitors, regulates, and directs internal hardware operations.

  • Central Processing Unit (CPU) / Microprocessor: Combines the ALU and Control Unit on a single integrated chip.

  • Memory Unit: Stores current program instructions and active operational data.

  • Input/Output (I/O) Unit: Manages hardware interfaces to external peripheral equipment.

  • Secondary Storage: Provides permanent, nonvolatile storage (e.g., magnetic hard disk drives).

• Computer Storage Concepts:

  • Bit: The primary atomic unit of data, holding a value of $0$ or $1$.

  • Byte: A grouping of $8$ bits representing a single distinct character.

  • Character Codes: Defined binary pattern mappings used to encode textual characters (e.g., ASCII, EBCDIC).

  • Number Codes / Two's Complement: System used to encode positive and negative integers into binary string representations using value boxes. Example conversion: Binary $10001101$ to base $10$ representation.

  • Word: A grouping of one or more bytes processed together as a unit to maximize data access speeds. The word size dictates the hardware limits for minimum and maximum storable integer values.

Common Programming Errors

• Writing and executing code immediately before fully analyzing and understanding problem specifications.

• Failing to implement routine, systematic source code and documentation backups.

• Failing to realize that computers follow explicitly written algorithms and cannot infer logical intent.

Here are the flashcards in Q&A format:

1. Q: What is a Computer Program (Software)?
   A: A self-contained set of instructions used to operate a computer to produce a specific result.

2. Q: What is a Software Development Procedure?
   A: A systematic process that helps developers understand the problem and construct an effective software solution.

3. Q: What is Software Engineering?
   A: A discipline focused on creating readable, efficient, reliable, and maintainable software programs and systems.

4. Q: What does Development and Design refer to?
   A: The first phase of program development which involves analyzing the problem, developing a solution, and coding it.

5. Q: What is a Program Requirement?
   A: A formal request for a program or an explicit statement describing a problem.

6. Q: What is an Algorithm?
   A: A step-by-step sequence of instructions detailing how data is to be processed to generate a desired output.

7. Q: What is Documentation?
   A: The process of creating required documents that describe the program and its functionalities.

8. Q: What does Maintenance involve?
   A: Ongoing correction of newly discovered bugs and adaptations to changing user requirements.

9. Q: What are Backup Procedures?
   A: Creating exact duplicate copies of program source code and documentation on a regular schedule.

10. Q: What is Machine Language?
    A: The only language that a computer can natively execute, composed entirely of binary numbers.

11. Q: What is Assembly Language?
    A: Uses symbolic mnemonics to replace binary opcodes and is translated into machine code.

12. Q: What is a High-Level Language?
    A: Languages that resemble written natural languages and can be executed across diverse hardware platforms.

13. Q: What is a Compiler?
    A: Translates all program statements at once into an executable program.

14. Q: What is a Debugger?
    A: A tool or process for locating and correcting bugs in a computer program.

15. Q: What is System Software?
    A: The set of control programs operating computer hardware.

16. Q: What is an Operating System (OS)?
    A: The comprehensive suite of system programs managing memory, CPU time, input/output, and storage.

17. Q: What are Programming Paradigms?
    A: Different approaches to programming, such as procedural and object-oriented programming.

18. Q: What does the Arithmetic and Logic Unit (ALU) do?
    A: It performs arithmetic calculations and logical comparisons.

19. Q: What is the purpose of the Input/Output (I/O) Unit?
    A: To manage hardware interfaces to external peripheral equipment.

20. Q: What is Secondary Storage?
    A: Nonvolatile storage that provides permanent data storage, such as hard drives.

21. Q: What is a Bit?
    A: The primary atomic unit of data holding a value of 0 or 1.

22. Q: What is a Byte?
    A: A grouping of 8 bits representing a single distinct character.

23. Q: What are Character Codes?
    A: Binary pattern mappings used to encode textual characters.