UFCFY5-30-1Multimedia Studio Scripting for Interactive Media Declaring and Using Arrays

UFCFY5-30-1Multimedia Studio Agenda Why Use an Array Array Declaration in Java Searching and Sorting an Array Using a for - next loop with Arrays Parallel Arrays Array Access Errors

UFCFY5-30-1Multimedia Studio Need to Store Five Numbers Use individual variables for each number stored: int numberOne; int numberTwo; int numberThree; int numberFour; int numberFive; messy - have to process as individual items rather than as a collection of grouped items. Solution - use an Array - contiguous data storage

UFCFY5-30-1Multimedia Studio Arrays and Data Storage Elements The value stored at array element number 2 is 14 Arrays store values in ‘elements’ (compartments) i.e. contiguous memory locations

UFCFY5-30-1Multimedia Studio Arrays and Data Storage Elements The array has 5 elements 0..4 The value stored at array element number 4 is 23 Array element numbering starts at Thus the size of the array is 5

UFCFY5-30-1Multimedia Studio Arrays and Data Types An Array of numbers (integers) Gibson Fender Aria Martin Array of strings Les Paul

UFCFY5-30-1Multimedia Studio Declaring Arrays in Java // create a new array [] numberArray = new int[5]; // store the numbers into the array // numberArray[0] = 15; numberArray[1] = 95; numberArray[2] = 14; numberArray[3] = 70; numberArray[4] = 23;

UFCFY5-30-1Multimedia Studio The for – next Loop // loops for a set number of times for (start; condition; increment) { // do something here }

UFCFY5-30-1Multimedia Studio Accessing Array Elements // iterate through the array for (int index = 0; index <= 4; index++) { System.out.println(numberArray[index]); } // outputs each number in the Array

UFCFY5-30-1Multimedia Studio System Output from for loop

UFCFY5-30-1Multimedia Studio Adding Array Elements // example of declaring specific(literal) values for an array int [] numberValues = {2, 5, 23, 37, 11, 19, 49, 6, 15, 41} ; int total = 0; for (int index = 0; index <= 9; index++){ total = total + numberValues[index]; } System.out.println("The total of all the numbers is:" + total);

UFCFY5-30-1Multimedia Studio Summing the Values of an Array 2 // total the numbers stored in the number array using array // length method int index;// loop control variable int sum = 0; for (index = 0; index <= numberArray.length; index++){ sum = sum + numberArray[index] } System.out.printl("The sum of the numbers in the array is " + sum)

UFCFY5-30-1Multimedia Studio Declaring String Arrays in Java // create a new array String [] nameArray = new String[5]; // store the names into the array nameArray[0] = “Bugs Bunny”; nameArray[1] = “Daffy Duck”; nameArray[2] = “Yosemite Sam”; nameArray[3] = “Mickey Mouse”; nameArray[4] = “Porky Pig”;

UFCFY5-30-1Multimedia Studio for..next loop to output contents for (int index = 0; index <= 4; index++){ System.out.println(nameArray[index]); }

UFCFY5-30-1Multimedia Studio System Output Bugs Bunny Daffy Duck Yosemite Sam Mickey Mouse Porky Pig

UFCFY5-30-1Multimedia Studio for..next loop to search for a match for (int index = 0; index <=4; index++){ if(nameArray[index] == "Mickey Mouse"){ System.out.println("Walt Disney Studios :" + nameArray[index]); } // end if else { System.out.println("Warner Bros. Pictures :" + nameArray[index]); }// end else } // end for

UFCFY5-30-1Multimedia Studio System Output from Search Warner Bros. Pictures :Bugs Bunny Warner Bros. Pictures :Daffy Duck Warner Bros. Pictures :Yosemite Sam Walt Disney Studios :Mickey Mouse Warner Bros. Pictures :Porky Pig

UFCFY5-30-1Multimedia Studio Typical Aspects of using Arrays Search an array for a given value Sort an array in a given order Find the size of the array Use the length method in searching algorithms Compare the contents of one array with another array

UFCFY5-30-1Multimedia Studio Beware! The classic runtime error is where a program tries to access an array element beyond the array’s size. for (index = 0; index <=5; index++) The array has only five elements, but the code is attempting to access element number six (5), which does not exist. The computer speak is the code has ‘fallen off the end of the array’

UFCFY5-30-1Multimedia Studio Parallel Arrays name John Ben Freda Sue Mike

UFCFY5-30-1Multimedia Studio Parallel Array Search name John Ben Freda Sue Mike Search on name Extract on name

UFCFY5-30-1Multimedia Studio Parallel Array Search name John Ben Freda Sue Mike Search on name Find occurrences on name of

UFCFY5-30-1Multimedia Studio Arrays of Data (sounds) Array of.mp3 audio files footsteps.mp3 shell.mp3 siren.mp3 alarm.mp3 ambience.mp3

UFCFY5-30-1Multimedia Studio Summary Arrays are a fundamental structured data type in any programming language Arrays store values usually of the same type in a contiguous way which allows the data to be accessed and manipulated as a collection of data Typical array access is to search and sort the contents Associated data may be held in parallel arrays and use cross referencing to extract the required information Algorithms that manipulate arrays must stay within the array bounds or runtime errors will occur causing the program to ‘freeze’ or ‘crash’.

UFCFY5-30-1Multimedia Studio Revise Last Week’s Concepts Three new coding structures and one new variable type

UFCFY5-30-1Multimedia Studio The Lottery Draw How will this week’s new concepts help to code a solution to the Lottery Draw scenario?

UFCFY5-30-1Multimedia Studio Tutorial Example AFI Movies The first of the American Film Institute (AFI) 100 Years series of cinematic milestones. AFI's 100 Years…100 films is a list of the 100 best American films, as determined by the American Film Institute from a poll of more than 1,500 artists and leaders in the film industry who chose from a list of 400 nominated films. The 100-best list was unveiled in 1998.

UFCFY5-30-1Multimedia Studio Parallel Arrays filmList and userRating filmList userRating Citizen Kane Casablanca The Godfather Gone with the Wind Lawrence of Arabia

UFCFY5-30-1Multimedia Studio Parallel Arrays filmList and userRating Citizen Kane Casablanca The Godfather Gone with the Wind Lawrence of Arabia element 0 not used

UFCFY5-30-1Multimedia Studio var filmList:Array = new Array(); filmList[1] = "Citizen Kane"; filmList[2] = "Casablanca"; filmList[3] = "The Godfather"; filmList[4] = "Gone with the Wind"; filmList[5] = "Lawrence of Arabia";. filmList[99]= "Guess Who's Coming to Dinner"; filmList[100]= "Yankee Doodle Dandy"; AFI Movies Array- filmList

UFCFY5-30-1Multimedia Studio var userRating:Array = new Array(); userRating[1] = 7; userRating[2] = 6; userRating[3] = 8; userRating[4] = 3; userRating[5] = 9;. userRating[99] = 2; userRating[100] = 7; AFI Movies Array- userRating

UFCFY5-30-1Multimedia Studio var index:int // loop variable for the for loop index // two functions to initialize the data setFilms();// initializes the film list setRating(); initializes the user-ratings Index Loop Variable and Array Initialization

UFCFY5-30-1Multimedia Studio // output all the films in the filmList array for(index=1; index <= 100; index++){ trace(filmList[index]); } Output all the films in the filmList Array

UFCFY5-30-1Multimedia Studio // output all the films in the array // and show the user rating for(index=1; index <= 100; index++){ trace(filmList[index] + " " + userRating[index]); } Output all the films and show the user rating

UFCFY5-30-1Multimedia Studio // output all the films where userRating > 7 for(index=1; index <= 100; index++){ if(userRating[index] > 7){ trace(filmList[index] + " " + userRating[index]); } Output all the films with a user rating greater than 7

UFCFY5-30-1Multimedia Studio // output all the films where userRating = 5 for(index=1; index <= 100; index++){ if(userRating[index] == 5){ trace(filmList[index] + " " + userRating[index]); } Output all the films with a user-rating of 5

UFCFY5-30-1Multimedia Studio correct if(userRating[index] == 5)comparison incorrect if(userRating[index] = 5)assignment this will output all the movies! Watch Out for a Logical Error!

UFCFY5-30-1Multimedia Studio // use the these lecture slides to carry out the exercises // e.g. output all the films in the filmList array for(index=1; index <= 100; index++){ // put your code here } Tutorial with Working Code for you to Modify