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Table of Contents

I. AP Computer Science

About the AP Computer Science Exam

17m 11s

- Intro0:00
- Roadmap0:16
- Java Editor0:45
- The AP Computer Science Exam1:30
- When It's Administered1:31
- Final Score1:49
- College Credit2:08
- Format of AP Exam Questions2:20
- Two Sections2:26
- Section 12:31
- Section 22:40
- Scoring3:23
- Multiple Choice Questions3:57
- Example4:04
- Check Answer in Java Editor5:06
- Keep in Mind6:21
- Multiple Choice, Multiple Answers6:58
- Evaluate Each Roman Numeral Separately7:08
- Example Multiple Choice Question7:34
- Java Editor8:35
- Free Response Questions12:25
- Example12:40
- Java Editor14:35
- AP Java Subset17:06
- What It Is17:37
- Primitive Types18:49
- Arithmetic Operators19:11
- Assignment Operator19:46
- Combined Arithmetic / Assignment Operators19:51
- Increment / Decrement Operators20:13
- Relational Operators20:36
- Logical Operators21:06
- Numeric Casts21:44
- Numeric Wrapper Classes22:39
- Math Library Methods23:08
- String Operations23:50
- User Input25:33
- Output27:17
- Program Invocation28:13
- Arrays29:06
- Lists29:52
- Control Structures30:47
- Methods31:27
- Classes32:10
- Inheritance33:09
- Exceptions34:22
- Tips for Taking the Exam34:55
- Before the Exam35:04
- During the Exam36:58
- Summary39:27

Types, Variables, & Arithmetic Operators

23m 20s

- Intro0:00
- Roadmap0:11
- Primitive Data Types0:37
- Int1:48
- Double2:42
- Boolean3:53
- Variables4:04
- Declaring a Variable4:16
- Assigning a Value6:01
- Declaring and Assigning on the Same Line6:36
- Casting7:00
- Mixing Types7:10
- Automatic Casting8:31
- Find Variables - Constants9:21
- Final Variables9:40
- Constants Written in All Capitals10:43
- Arithmetic Operators11:59
- Five Arithmetic Operators12:10
- Result Depends on Type of Operands13:49
- Assignment Operators14:59
- Compound Assignment Operators15:13
- Examples15:43
- Increment / Decrement Operators17:08
- Add 1 (++)17:37
- Subtracts 1 (--)18:25
- Summary21:41

Equality, Relational, & Logical Operators

22m 34s

- Intro0:00
- Roadmap0:11
- Equality and Relational Operators1:09
- Equal to1:15
- Not Equal to2:25
- Relational Operators2:40
- Logical Operators3:44
- Three Operators: And, Or, Not3:53
- AND Defined4:18
- OR Defined4:50
- NOT Defined5:19
- Example: And5:43
- Example: Or6:23
- Example: Not6:41
- Truth Tables7:16
- Truth Tables for AND7:30
- Truth Tables for OR8:05
- Truth Tables for NOT8:47
- Short-Circuit Evaluation10:03
- Example10:32
- This Behavior Can be Useful in Program Design12:29
- De Morgan's Laws13:53
- First Law14:04
- Second Law14:29
- Operator Precedence15:28
- List of Operators in Highest to Lowest Precedence15:38
- Evaluation on Operators17:30
- Summary20:26

Input, Output, & Errors

24m 7s

- Intro0:00
- Roadmap0:11
- Getting Input from the User0:42
- For AP Questions, Will Look Like One of the Following0:54
- One Method of Getting Input From the User2:50
- Scanner Class3:20
- Providing Output to the User4:38
- Only 2 Included in AP Subset5:06
- Example: Print Two Strings on the Same Line5:45
- Example: Print a String and an Integer6:16
- Example: Print a Blank Line6:40
- Java Code Example7:04
- Escape Sequences11:10
- Backslash Character Followed by One or More Additional Characters11:23
- Newline Character11:49
- Double Quote Character12:39
- Backslash Character13:48
- Java Code Examples: Printing Escape Sequences14:43
- Exception Handling16:25
- Describe As16:33
- Exceptions Within the AP Subset That Provides Structured Way to Handle Errors17:18
- Java Code Example19:40
- Summary22:21

Conditional Statements

28m

- Intro0:00
- Roadmap0:09
- Conditional Statements0:55
- Based on Value of a Boolean Expression1:40
- Switch Statement2:42
- The If Statement2:59
- Structure of If Statement3:06
- The If-Else Statement4:46
- The If-Else Statement6:02
- If expression - False6:34
- Nested If-Else Statements7:13
- 'Nest'7:28
- Nested If-Else Statements7:56
- First Thing to Determine9:28
- Code10:24
- The Extended If Statement13:14
- Code15:45
- The Switch Statement18:54
- The Way It Works19:37
- Example: Switch Statement in a Java Program22:44
- Summary27:03

Loops

32m 29s

- Intro0:00
- Roadmap0:07
- Repeating an Action0:53
- Example1:03
- Repeating an Action1:21
- Use Brute Force Method1:32
- The While Loop2:16
- To Repeat An Action2:55
- Example: While Loop4:57
- The Do Loop5:53
- Example: Do Loop8:00
- Distinction of Do Loop & While Loop9:04
- The For Loop10:30
- The Way It Works10:41
- Example: The For Loop12:43
- The Enhanced for Loop14:18
- The Way It Works14:42
- Example:Enhanced for Loop16:32
- Nested While Loops19:06
- Example19:33
- Example: Nested While Loop (Code)20:47
- Nested For Loops22:36
- Example22:51
- Example: Nested For Loop (Code)23:29
- The Return Statement24:30
- Example25:03
- The Break Statement26:21
- The Continue Statement28:01
- Summary30:56

Strings

42m 20s

- Intro0:00
- Roadmap0:25
- Literal Strings1:27
- Class: Strings1:38
- String Is Immutable2:11
- Example2:53
- Literal Strings3:27
- String Variables4:24
- Example: String Variable5:56
- String Concatenation7:03
- Example7:37
- Example: String Concatenation8:26
- String Concatenation10:00
- Assignment Operator10:11
- Example10:48
- Example: String Concatenation11:25
- String Length13:05
- Example: String Length14:16
- String Comparison16:04
- Equals Method16:37
- Example: String Comparison17:08
- String Comparison21:40
- String.Equals: Case-Sensitive21:49
- Equals Ignore Case: Case-Insensitive22:14
- Example: Case-Sensitive and Case-Insensitive Comparison22:46
- String Comparison25:38
- Compare To (String.compareTo)25:53
- Example27:27
- Example: Sting Comparison Using the compareTo Method28:15
- Taking a Subset of a String30:34
- Substring Method30:59
- 2 Versions31:08
- 1st Version: Takes One Parameter31:27
- 2nd Version: Takes Two Parameters32:41
- Example: Substring34:02
- Searching Within a String36:04
- indexOf Method36:12
- 1st Version: Takes One Parameter36:26
- 2nd Version: Takes Two Parameters37:27
- Searching Within a String38:36
- lastIndexOf Method38:53
- 1st Version: Takes One Parameter39:08
- 2nd Version: Takes Two Parameters39:28
- Summary40:43

Arrays

47m 2s

- Intro0:00
- Roadmap0:14
- Declaring and Creating an Array0:49
- Array Defined0:55
- 1st Way to Declare and Create and Array1:10
- 2nd Way to Declare and Create and Array2:15
- Referring to Elements in an Array5:12
- Integer Expression5:39
- Code Example: Declaring and Creating Arrays7:26
- Referring to Elements in an Array9:12
- Example9:45
- Code Example: Looping Through an Array of Ints12:23
- Referring to Elements in an Array15:35
- Enhanced for Loop15:42
- Code Example: Looping Through an Array of Strings With an Enhanced for Loop17:19
- Referring to Elements in an Array19:25
- ArrayIndexOutOfBoundsException19:37
- Code Example: Array Index Out of Bounds Exception21:03
- Resizing Arrays23:05
- Example23:33
- Code Example: Resizing Arrays25:15
- Copying Arrays28:13
- Passing an Array to a Method30:09
- Example30:15
- When Calling This Method: Pass in an Array33:40
- Code Example: Passing an Array to a Method34:06
- Returning an Array From a Method36:02
- Create a Method36:12
- Calling This Method38:42
- Code Example: Returning an Array to a Method39:24
- Two-Dimensional Arrays42:23
- Length Method43:17
- Number of Columns43:42
- Summary45:00

Classes & Objects

47m 33s

- Intro0:00
- Roadmap0:46
- Classes and Objects2:03
- Class2:17
- Object2:34
- Constructors3:43
- Constructors5:34
- Methods7:11
- Example: getName Method7:44
- Methods8:45
- Example9:08
- Example in Java Program10:19
- Data Fields12:48
- Way to Find Data Fields13:10
- Data Fields13:50
- Example: Instantiate Two Objects with Different Instance Data14:43
- Return Type16:21
- A Primitive Type16:37
- An Object of a Class Type16:49
- Return Type17:25
- Access Control18:19
- Public, Protected and Private19:31
- Assumptions Made in AP Java Subset20:00
- Access Control20:58
- Definition of Public21:08
- Definition of Protected21:18
- Definition of Private21:28
- Guidelines on What to Make Public/ Private21:36
- Accessors and Modifiers24:47
- Accessor25:35
- Modifier or Mutator26:24
- Static vs. Instance27:15
- Static Member27:26
- Example: Static vs. Instance27:59
- Code Example30:19
- Passing Data to Method34:00
- Code Example36:17
- Getting Data Back From Methods37:28
- To Make Use of a Return Value37:53
- Code Example38:51
- Overloaded Methods39:39
- Signature Includes40:19
- Signature Does Not Include40:45
- Example: Overloaded Methods43:52
- Overloaded Methods44:19
- Summary45:00

Inheritance & Polymorphism

31m 30s

- Intro0:00
- Roadmap0:42
- Inheritance1:14
- Subclass1:56
- Superclass2:07
- Inheritance3:08
- Example3:36
- Inheritance4:44
- Subclass Does Not Inherit…6:05
- Inheritance7:06
- To Override a Method7:17
- Inheritance8:59
- Example10:24
- Class Hierarchies11:31
- Multiple Level Hierarchies for Subclass12:41
- Abstract Classes14:35
- Example15:59
- Polymorphism20:19
- Example20:34
- Interfaces22:33
- Interfaces Example25:13
- Defines 3 Methods25:27
- Summary29:26

Lists

33m 15s

- Intro0:00
- Roadmap0:16
- Lists0:52
- Wrapper Classes1:10
- The List Interface2:37
- Cannot Instantiate a List3:26
- The ArrayList Class5:01
- The Way It Works7:45
- The ArrayList Class8:34
- Primary Methods Needed To Use for ArraryList8:53
- Code Examples16:26
- The LinkedList Class21:01
- To Instantiate a LinkedList…21:59
- Code Example24:05
- ArrayList vs. LinkedList25:25
- Internal Storage Implementation of ArrayList25:35
- Internal Storage Implementation of LinkedList26:01
- Pros/Cons of Each26:23
- Summary32:10

Numeric Wrapper Classes & Mathematical Functions

23m 14s

- Intro0:00
- Roadmap0:11
- Numeric Wrapper Classes0:42
- To Get Around Storing Limitation1:19
- Setting and Getting Values2:30
- Double Class3:57
- Comparing Values5:07
- Equals Method5:22
- Comparing Values7:16
- CompareTo Method: Integer Class7:29
- CompareTo Method: Double Class9:24
- Minimum and Maximum Values10:28
- Integer Class: Publib Static Final10:56
- Double Class12:19
- Automatic Conversion12:53
- Autoboxing13:12
- Example13:36
- Get Method14:52
- The Math Class15:59
- Math.E16:18
- Math.PI16:25
- Example16:34
- The Math Class17:07
- Working With Random Numbers18:42
- Example19:47
- Summary22:14

Algorithms: Iteration

25m 43s

- Intro0:00
- Roadmap0:13
- Iteration0:36
- Iteration Defined0:39
- For Loop / While Loop0:50
- Example1:11
- Iteration3:11
- Two-Dimensional Range3:19
- Using Two Nested While Loops5:00
- Finding Minimum and Maximum Values5:54
- Finding Minimum and Maximum Values Examples7:50
- Finding Minimum and Maximum Values Example12:52
- Inserting in Order15:19
- Inserting in Order Code17:42
- Loop Invariants21:53
- Example23:17
- Summary24:37

Algorithms: Recursion

27m 30s

- Intro0:00
- Roadmap0:09
- Recursion0:44
- Calculating Factorials2:49
- n! and How It's Defined3:01
- Recursive Implementation of the Factorial Function in Java3:34
- Calculating Factorials4:34
- Calculate 4!4:35
- Factorial Function in Java7:22
- Calculating Fibonacci Numbers9:19
- Fibonacci Numbers Defined9:30
- Recursive Implementation10:33
- Implementation in Java10:44
- Calculating Fibonacci Numbers11:28
- Calculate Fibonacci(4)11:29
- Fibonacci in Java14:59
- Other Recursive Functions17:35
- Other Recursive Functions21:32
- Calculate Mystery(4)21:33
- Mystery in Java22:29
- Important Considerations23:49
- Recursive Methods25:15
- Summary26:41

Algorithms: Sorting

29m 42s

- Intro0:00
- Roadmap0:08
- Sorting0:55
- Definition of Sorting1:05
- Cant Sort Any of the Following1:14
- Selection Sort3:49
- Definition of Selection Sort3:58
- 'Search-and-Swap' Algorithm5:05
- Selection Sort Example7:46
- Insertion Sort10:57
- Insertion Sort Example13:02
- Merge Sort15:14
- Recursive Sorting Algorithm16:15
- Merge Sort Example18:03
- Quick Sort20:34
- Recursive Sorting Algorithm21:36
- Quick Sort Example23:35
- Summary27:19

Algorithms: Searching

32m 37s

- Intro0:00
- Roadmap0:08
- Searching0:40
- Sequential Search2:22
- Performed on Any Array2:29
- Sequential Search Algorithm Using a For Loop4:24
- Java Example6:28
- Binary Search8:51
- Binary Search Algorithm Using a While Loop12:03
- Java Example16:59
- Binary Search20:38
- Recursive Method20:53
- Java Example: Using Binary Search25:34
- Search Considerations28:16
- Binary Search29:14
- Summary31:14

Program Design & Development

29m 29s

- Intro0:00
- Roadmap0:41
- Object-Oriented Programming1:20
- Definition1:35
- Encapsulation2:26
- Polymorphism4:43
- Top-Down Design and Development5:56
- Top-Down Design6:10
- Top-Down Development6:51
- Reusable Code8:47
- Definition8:58
- Example to Reusable Code10:33
- Team Development11:36
- Team Development15:03
- Adding Another Developer15:23
- Data Structure19:28
- Definition19:35
- Examples19:44
- User Interface20:53
- Definition21:00
- Specifications24:19
- Definition24:29
- 2 Important Purposes for Specifications25:25
- Summary27:27

Standard Classes & Interfaces

32m 53s

- Intro0:00
- Roadmap0:13
- Object1:46
- Methods1:57
- Equals Method2:06
- toString Method2:16
- What Else To Know2:28
- Integer3:19
- Constructor3:32
- Methods3:51
- Constants4:28
- What Else To Know5:05
- Double6:14
- Constructor6:35
- Methods6:50
- What Else To Know7:06
- String8:16
- Methods8:40
- What Else To Know12:10
- Math15:24
- Methods15:36
- What Else To Know18:13
- List20:02
- Methods20:30
- ArrayList22:45
- What Else To Know23:27
- Test-Taking Tips26:05
- Summary29:47

II. AP Test Preparation

Multiple Choice Question Tips & Practice

55m 47s

- Intro0:00
- Roadmap0:23
- AP Computer Science Exam Structure1:32
- Two Sections1:40
- Contribution to Score3:35
- Multiple Choice Strategies and Tips4:50
- Example Question 19:07
- Example Question 213:34
- Example Question 316:12
- Example Question 421:44
- Example Question 526:41
- Example Question 634:12
- Example Question 739:41
- Example Question 842:09
- Example Question 946:31
- Example Question 1050:35
- Summary54:49

Free Response Question Tips & Practice

40m 55s

- Intro0:00
- Roadmap0:27
- AP Computer Science Exam Structure1:15
- Two Sections1:20
- Contribution to Score2:09
- Free Response Strategies and Tips3:23
- Free Response Strategies and Tips Continued6:17
- Free Response Strategies and Tips Continued10:22
- Free Response Strategies and Tips Continued13:00
- Free Response Strategies and Tips Continued15:42
- Example Free Response Question17:41
- Example Free Response Question Narrative Continued18:30
- Example for Problem19:29
- Example Set-Up for Problem19:56
- Example Set-Up for Problem Continued21:48
- Code24:14
- Code Continued: First Method25:36
- Second Method26:28
- Additional Narrative27:04
- Definition of Part A: What They Want You to Write27:33
- Definition of Part B: What They Want You to Write28:50
- Requirements for Part A31:06
- Part A: One Possible Solution31:49
- Requirements for Part B34:06
- Part B: One Possible Solution34:48
- Summary39:52

The GridWorld Study

54m 18s

- Intro0:00
- Roadmap0:19
- Overview of GridWorld0:51
- Definition of GridWorld1:00
- Important part of AP Exam3:14
- Need to Understand It5:16
- Overview of GridWorld: Testable APIs8:00
- API Defined8:06
- Testable APIs8:52
- Testable Code9:22
- 4 Classes9:57
- Location Class10:21
- Location Class: 8 Public Constants That Help with Direction11:36
- Row Numbering12:32
- Column Numbering13:13
- Location Class: 7 Public Constants That Represent Turns13:31
- Location Class: Methods Useful in Navigating Through the Grid15:25
- getAdjacentLocation15:34
- getDirectionToward16:21
- Location Class: 3 Other Useful Methods16:58
- Equals Method17:05
- CompareTo Method17:35
- ToString Method18:16
- Grid Interface18:41
- Represents18:50
- Grid Interface: Useful Methods20:34
- getNumRows Method20:42
- getNumCols Method20:52
- isValid Method21:00
- Grid Interface: Useful Methods22:16
- Put Method22:23
- Remove Method22:13
- Get Method23:26
- Grid Interface: Useful Methods23:44
- GetOccupiedLocations Method23:55
- GetValidAdjacentLocations Method24:21
- GetEmptyAdjacentLocations Method25:02
- GetOccupiedAdjacentLocations Method25:24
- Grid Interface: Useful Methods25:37
- GetNeighbors Method25:44
- Actor Class26:27
- Constuctor: Actor27:02
- GetColor Method27:31
- SetColor Method27:38
- GetDirectionToward Method27:46
- SetDirection Method28:09
- GetGrid Method28:27
- GetLocation Method28:40
- PutSelfInGrid and RemoveSelfFromGrid Method28:51
- MoveTo Method30:03
- Act Method30:17
- ToString Method31:24
- Rock Class31:46
- 3 Methods31:58
- Flower Class32:35
- 3 Methods32:51
- Bug Class33:53
- Includes These Methods34:34
- How the Move Method Works36:38
- CanMove Method38:53
- BoxBug Class40:49
- Behavior41:00
- 2 Private Variables41:20
- Constructor for BoxBug41:55
- BoxBug Class Methods42:16
- Critter Class43:41
- How It Works44:03
- Next Step45:38
- 3rd Step47:01
- Last Step in Act Method48:33
- ChameleonCritter Class49:00
- Redefines Some Characteristics of Critter Class49:26
- Another Difference51:02
- Summary52:25

Multiple Choice Questions About GridWorld

41m

- Intro0:00
- Roadmap0:16
- Multiple Choice Strategies and Tips0:45
- Structure0:49
- Points Worth1:47
- Some Strategies and Tips3:29
- No Penalty for Wrong Answer6:10
- Some Strategies and Tips Specifically on GridWorld Questions6:29
- Some Strategies and Tips Specifically on GridWorld Questions9:37
- GridWorld Testable APIs and Code13:17
- Testable APIs13:25
- Testable Code13:47
- Example Question 114:32
- Example Question 217:11
- Example Question 322:53
- Example Question 426:17
- Example Question 534:11
- Summary39:47

Free Response Questions About GridWorld

39m 31s

- Intro0:00
- Roadmap0:14
- Free Response Strategies and Tips0:49
- Format0:56
- Points1:18
- Quick Reference Guide1:49
- Not Required to Do in Order2:48
- Multiple Parts3:33
- All Answers Must Be Written in Java5:00
- Partially Correct Solutions Can Be Awarded Partial Credit7:49
- Write Neatly10:40
- Don't Waste Time12:52
- GridWorld Testable APIs and Code14:55
- Testable APIs15:05
- Testable Code15:53
- GridWorld Testable APIs and Code16:37
- GridWorld Free Response Question16:41
- Example17:34
- Example Free Response Question18:23
- Question18:54
- Visual Diagram of the Game Board20:00
- Visual Chart21:08
- Narration Continues21:56
- The Piece Class22:59
- Narration Continues23:59
- What You Will Need to Do24:28
- The Rest of the Definition for DropGame25:08
- Part A: Requirements25:55
- Part B: Requirements28:44
- Part A: Question (Again)31:54
- Part A: One Possible Solution32:19
- Part B: Question (Again)35:30
- Part B: One Possible Solution35:47
- Summary38:34

Final Tips for Taking the Exam

27m 38s

- Intro0:00
- Roadmap0:10
- AP Computer Science Exam Structure0:46
- Two Sections0:49
- Scoring1:24
- Multiple Choice Strategies and Tips2:15
- Answer Questions for Descriptive Paragraph First2:38
- No Penalty for Wrong Answer3:42
- Free Response Strategies and Tips4:00
- Each Part Graded Separately4:57
- All Answers Written in Java5:54
- Partially Correct Solutions8:32
- Write Neatly10:33
- Draw a Single Line Through Mess-Ups13:09
- Additional Resources14:49
- Download the Project Files for GridWorld15:20
- Download Reference Documents15:39
- Remember, You Can Watch This Lesson More Than Once15:54
- What to Bring to Your Exam16:19
- What Not to Bring to Your Exam18:47
- The Night Before Your Exam22:00
- The Day of Your Exam24:23
- Summary26:44

Glossary of Terms to Know

36m 31s

- Intro0:00
- Roadmap0:16
- Abstract Class1:28
- Array2:29
- Casting3:43
- Class4:39
- Conditional Statement5:35
- Constructor6:28
- Escape Sequence7:18
- Exception8:24
- Final Variable8:59
- Inheritance10:19
- Instance11:36
- Interface12:33
- Iteration13:08
- List14:05
- Logical Operator15:11
- Loop16:20
- Loop Invariant17:06
- Method17:30
- Numeric Wrapper Class18:55
- Overloading20:38
- Polymorphism21:10
- Primitive Data Type23:22
- Public and Private24:06
- Random25:03
- Recursion27:07
- Return Type28:08
- Searching28:59
- Signature30:14
- Sorting30:51
- Static32:40
- String33:37
- Subclass and Superclass34:30
- Glossary35:37

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0 answers

Post by Basit Khan on January 16, 2017

Dr. Quayle,

after attending the java loops, I had a following exercise to solve;

In one of the introductory courses in a university, passing students are assigned a final grade of the uppercase letter P or lowercase p while failing students are assigned the letter F or f. Write a Java program that asks the user to enter grades (P/p or F/f) for 30 students, then calculates and displays both percentages of the passing and failing students.

I tried to solve it but to be honest I struggle to apply the syntax and formula. My main issue is that after reading and listening to the lecture I'm not able to apply it to create a program, kindly Help!

thanks

Omair

1 answer

Last reply by: Professor Quayle

Fri Oct 2, 2015 12:25 AM

Post by Malik Hall on September 23, 2015

Hi Professor Quayle,

I saw an example in a textbook that I did not understand about loops. This example showed SENTINELs, DecimalFormat, Scanners, and the highlighted word new. Could you explain these to me please because I have a difficult time understanding these in class since my teacher uses SENTINELs and Scanners in his examples.

https://drive.google.com/file/d/0B4eQm5IOB_khdFRFQTVFTUlZaTQ/view?usp=sharing

1 answer

Last reply by: Professor Quayle

Tue Mar 11, 2014 12:19 AM

Post by Zelong Zhao on March 9, 2014

well, all of questions above are very cool.

I still cannot understand what means of "break" and "returen"

What should I do?

I am not a english native speaker, so which book should I read. PS: In my personal dictionary, "understand" means I know What is it && Why we need it.

For example, What is the logic form of Break and Returen? Why Java includes those.

I know those are big questions and even do not be included in AP Subscribes but I really want to try to know those.

It is honor to get your lessons.

1 answer

Last reply by: Professor Quayle

Tue Nov 19, 2013 12:03 AM

Post by Ashna Ayub on November 17, 2013

Professor Quayle,

I have been able understand how to write a for loop in terms of syntax, but I don't really understand how to read the code which is why I am stuck on this problem:

Consider the following array:

int[] a = { 1,2,3,4,5,4,3,2,1, 0 }

What is the value of total after the following loops complete? (by looking at the for loop)

int total = 0;

for (int i = 0; i < 10 ; i = i +2 ) {total = total + a[i]; }

Could you please explain how to find the total by looking at the loop?

1 answer

Last reply by: Professor Quayle

Sat Oct 13, 2012 10:11 AM

Post by William Gould on October 13, 2012

Dr Quayle,

I am doing an assignment that doesn't seem to be working and i wanted to ask if you could help me understand whats going on.

my assignment is to develop a new class called MathTasks and create a method called productFor, productWhile, and productDoWhile that has a strictly positive integer parameter n and computes and returns the product of all the integers from 1 to n (inclusive of n).

here is my code so far (its very messy so far because im brand new to coding)

public class MathTasks

{

public MathTasks()

{ }

public void productFor(int n) {

for (int i = 1; (1 > 0) && (i <= n); i++)

{

System.out.print (n * 1);

System.out.print ("n = " + n);

} }

public void productWhile(int n)

{

while ((1 > 0) && (i <= n)){

{

System.out.print (n * 1);

System.out.print ("n = " + n);

}

}

}

public void productDoWhile (int n) {

if (n > 0) {

}

do {

System.out.print(n * 1);

System.out.print("n = " + n); }

while ((1 > 0) && (i <= n));

} }

Could you help explain to me how this works and what i am doing wrong?

1 answer

Last reply by: Malik Hall

Fri Sep 18, 2015 10:09 PM

Post by Brad Cherry on September 17, 2012

I am currently doing something like this and I am just beginning to understand this but I am still a bit lost, I use JCreator java program and I go with my class and I am stressed out and over worked any way I can keep up we get homework every Monday and it is due the next Tuesday and we get more than a few programs to make and that for me is too much pressure since I have little java experience