Coding Suggestions and Rules of Thumb

"Measuring software productivity by lines of code is like measuring progress on an airplane by how much it weighs."

— Bill Gates

Some Things We Want to Achieve

• create/modify programs efficiently
• less likely to introduce errors (bugs) into code
• create efficient program
• ease of maintaining/modifying code

Approaches: Top-down and Bottom-up

• illustration

Algorithms

• Create one with pen and paper
• Use pseudo code
• Does not need to be (and probably should not be) valid C++ syntax
• Features of an Algorithm [Knuth]
  • Finiteness
    Eventually completes
  • Definiteness
    Precisely defined
  • Output
    Result of the computation
  • Input
    Objects/data given before algorithm begins
  • Effectiveness
    Sufficiently basic operations to solve a specific class of problems

Use Functions

• Abstraction
• Decomposition

Compile vs Runtime Errors

• Prefer compile-time errors to run-time errors
• 100% of compile time errors are detected, not so with runtime errors
• E.g., use const to more fully express your intentions

Minimize Redundancy

• Ideally, each characteristic of the program is included once (both implicitly and explicitly)
• Error prone/tedious/time consuming to maintain the redundancy
• E.g., easy to overlook changing one of the pieces that are redundant but forget to change other(s)

Minimize Dependency

• Difficult to detect adverse effects when making changes to code
• Increases code reuse
• E.g., code that is not dependent on an application can more easily be shared among many applications. This is one feature of libraries.