<aside> 💡 loops, conditionals, classes

</aside>

conditionals

• perform different actions depneidng on whether a boolean condition evaluates to true or false

• if condition is true, one set of statement is executed. otherwise, another set of statements is executed

  

  

  multiple alternatives

  • more than two cases, resulting in code w multiple branches
  • if you have multiple if statements, test against the largest cutoff first

  

  relational operators

  

  comparing strings: .equals() vs ==

  • when comparing strings in a conditional statement, make sure to check for equality using .equals() and not ==

  • == checks to see whether the strings are stored in the same location, not whether their contents are the same

    

  boolean operators

  • used to combine multiple boolean conditions
  • && (and) operator returns true when both conditions are ture
  • || (or) operators returns true if at least one condition is true
  • ! (not) operator negates or inverts a condition

  

  loops

  • execute instructions until goal is reached

  • while loops: as long as Boolean condition is true, the statements inside the while statement are executed

    • loop condition is checked first and before every time the loop iterates
    • structure:

    while (condition)...
    

    

    • better to use when you don't know exactly how many times the loop will run

• for loops: used when a value runs from starting point to an ending point with a constant increment or decrement (step size)

  • structure:

  for (initalization; condition; update)...
  

  • initalization is executed once, the condition the checked before each iteration, and the update is executed after each iteration

    

  • better to use when you know before hand how many times the loop will be run

objects and classes

what are classes?

• a unit of organization in your code (one public class per file)
• a blueprint for the objects you are mkaing
• classes we already know: Math, String
• tip: you can usually identify a class because names are capitalized
  • Math.pow(4,3); or String name = "Chianna";

3 main components of a class

• fields/instance variables - attributes
  • hair color, height, weight
• constructors - instatiates your object, initalizes the instance variables
• methods - actions
  • run(), leap(), dance()

variables and data types

• local variables v. instance variable
• primitive data types are in lower case: int, boolean, char, etc
  • you cannot call methods in them
• must always declare before you use the variable

instance variables