/Java-Notes

Primary LanguageJava

Today

  • Control flow / conditionals
  • Comparisons
  • Randomness

Recap

  • How do I create a new folder in the terminal?

  • What kind of variables are there in the args?

    • Strings; the arguments is an array of strings

  • What kind of variables are there?

    • Reference object variable

      • String
      • Integer

    • Primitives

      • int
      • double
      • char
      • float
      • boolean
      • short
      • byte
      • long

  • What is the Modulo?

    • Remainder of a division
    • Useful for example with "do something for every 5th item on a list"

  • Increment/Decrement

    • What does this do myNumber += 7;

      • exactly the same as myNumber = myNumber + 7
      • A special assignment operator
      • Plus seven to mynumber

    • myNumber++ is an increment, it always adds just 1 to a number

    • Recap.java

Basic control flow

  • Who here has any idea what I am talking about when I say "control flow"?

  • A program flows from one instruction to the next

    String name = "Rauli Thunderkitten";        // Executed first
System.out.println("My cat is " + name);    // Executed second
System.out.println(name + " is the best");  // Executed third

  • "If statements" is an example of controlling this flow

    • The decision part of a flowchart
    • Also called conditionals (or condition)

  • Example: PetGreeter.java

Randomness

  • Java has a built-in RNG - Random Number Generator
  • Example: Rando.java

Switch & parseint

  • Switch statements are an alternative to if statements

  • Sometimes we can have a LOT of things to check

    • The switch statement can check one or more conditions
    • It CAN be easier to read
    • Divides opinions

  • Example: MonthChecker.java