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CSCE 146 Hey Remember Java? Written by: Dr. JJ Shepherd.

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Presentation on theme: "CSCE 146 Hey Remember Java? Written by: Dr. JJ Shepherd."— Presentation transcript:

1 CSCE 146 Hey Remember Java? Written by: Dr. JJ Shepherd

2 Objectives Review the basics of Java Variables Branch Statements Loops Arrays Classes Inheritance Exceptions

3 Website www.cse.sc.edu/~shephejj/csce146/ Still under construction but will be up soon!

4 145 Was Sure Neat Hey you passed! – That’s pretty rad Let’s review!

5 Variables Used to store information Has a defined size Two Types of Variables Primitive Types – int, double, char Class Types – String, PrintWriter, Exception

6 Variables Defining Variables Tells the computer to allocate storage in memory given a name Concept Example > >; int tacosConsumed; String tacoConvo;

7 Variables Initializing and Assigning Variables Sets variable to a defined value Concept Example > = >; tacosConsumed = 20; tacoConvo = “I ate “ + tacosConsumed + ” tacos. I feel sick now”;

8 Branch Statements Used for decision making problems If statement concept if( >) { > }

9 Branch Statements Else statements are the catch all of if statements Only exist if there is a prior if statement Else Concept if( >) { > } else { > }

10 Branch Statements Else if’s are short handed if statements in else statements Else if concept else if( >) { > } else { if( >) { > }

11 Branch Statements Switch statements are specialized branch statements that has cases which can be integers, characters, or Strings Switch concept switch( >) { case >: > break; case >: > break; … default: > break; }

12 Loops Loops repeat code until a boolean condition is no longer true While Loop Concept while( >) { > }

13 Loops For loops are used to loop the body a set amount of times For loop concept for( >; >; >) { > }

14 Loops Do while’s are dumb They stupidly run 1 to many times Concept do { > } while( >);

15 Arrays Arrays are collections of data of the same type Concept for declaring arrays Use a for loop to initialize each element in the array ***These are used a lot in this course*** >[] > = new >[ >];

16 Classes Blueprints to create objects Remember the steps – Define the class – Instance variables – Constructors – Accessors and Mutators – Additional Methods

17 Classes Defining the class Concept public class > { > }

18 Classes Instance variables are the attributes of the class Concept public class > { private > >; … }

19 Classes Constructs an instance of a class in memory and sets the instance variables to a value Default constructors have no parameters and set everything to a default value public >() { > }

20 Classes Parameterized Constructors have parameters that set one or all of the instance variables to a value Concept public >( >) { > }

21 Classes Mutators are used to modify instance variables in a class Adds a layer of protection by validating values Concept public void >( >) { this. > = >; }

22 Classes Accessors are used to get values of instance variables outside of the class Concept public > >() { return this. >; }

23 Classes Methods are behaviors of classes Used internally and externally Accessors and mutators are methods Concept > > > ( >) { > }

24 Classes Static methods are static in memory Used as helper methods that exist outside of one particular instance > static > > ( >) { > }

25 Inheritance Used to take the attributes and methods from a parent (super) class Concept public class > extends > { > }

26 Inheritance In inherited constructors need to all the parent’s constructor by calling “super” Concept To call inherited methods use “super.” super( >); super. >;

27 Interfaces Used as a blueprint to create classes. Classes are a blueprint to create instance of objects Only has method definitions Concept public interface > { >; … }

28 Interfaces Interfaces are the building concept of polymorphism To use an interface used “implements” Concept public class > implements > { > }

29 Exceptions Gracefully allows programs to crash and an exceptional event happens To create exceptions extend the/an exception class Then call the parent’s constructors

30 Exceptions Concept public > extends > { public >( >) { super( >) }

31 Exceptions Methods that can throw exceptions need to check for those cases Concept > > > ( >) throws > { … throw new >(); … }

32 Exceptions If a method throws an exception it must be called in a try catch block that handles the exception Concept try { >; } catch( > e) { System.out.println(e.getMessage()); }


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