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JavaScript Comments and Conditionals


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This is the slide stack to accompany the YouTube video of the same name at

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JavaScript Comments and Conditionals

  1. 1. JavaScript Comments and Conditionals Charles Russell Bennu Bird Media
  2. 2. Note Taking ● Detectives journal ● Fire Log ● Sketch books ● In programs we use comments
  3. 3. Comments are for people not machines ● Notes to others and ourselves describing our thinking. ● Often used to outline the program with pseudo code. ● Establish proprietary information like authorship copyright and other ● Documentation
  4. 4. Comments in JavaScript ● Single line comment // ● From where the comment begins to end of line ● Multi-line comment /* */ ● Begins with /* and continues to be ignored no matter how many lines until */ ● Documentation comment /** */ ● Used by documentation tools like Scriptdoc or Doxygen to document code in the code document and extract to either a sepeate document of web page.
  5. 5. Branching out ● It is very common to want to decide one of two paths for a program to take ● Statements that choose between multiple courses of action are called conditional statemens ● If statements provide that branch ● if (condition ) doSomething() else doSomethingElse() if (boolean) { statement1; statement2; }else{
  6. 6. Multibranch Selection ● If great for when you have only two possible paths ● What if you have many paths ● else if to the rescue if (condition) { doSomething } else if ( condition) { doAnotherThing } else{ doSomethingElse
  7. 7. Switch JavaScript's Manifold ● Switch is another way to branch into one of many paths ● Two other keywords needed for this statement – case: this is the conditional – break Breaks out of the switch ● Optional default keyword – This part of the switch is executed if no other condition is met
  8. 8. Switch the syntax switch (a) { case value: statements break; case value2: statements break; default: statements
  9. 9. Summary ● Comments allow to keep notes and document your code ● There are single line and multiline comment types ● A special multiline comment can aid in documentation ● Conditional statements allow branching to alter operational flow. ● { } define code blocks (and somethings we will get to soon) ● If ( conditional expression) {..}else if {..} else{..} – Else optional ● Switch is used for selecting from multiple code blocks
  10. 10. Next: Iterations