Arrays And Methods

Question 1

What are Primitive Data Types?

Answer 1

Static - set amount of memory, actual valve stored in memory location, pass by value
ex: int, double, boolean, float, etc

Question 2

What are Object Type variables?

Answer 2

Reference Type, memory set aside varies, pass by reference
ex: String, Array

Question 3

What is an array?

Answer 3

• Data structure that can hold multiple valves of the same type (advantage)
• can store primitive and non primitive data types (advantage)
• faster, takes less memory (advantage)
• fixed size - static (disadvantage)
• has less buit in methods (than array list) (disadvantage)
• Initializing: int[] list = new int [10];

Question 4

What is a 2D Array?

Answer 4

• an array of arrays (ex: chessboard)
• declaring: int [] [] array = new int [4] [3];

Question 5

What is an Arraylist?

Answer 5

• a class in java that can hold any type of object (No Primitive data types - boolean, char, int)
• can grow or shrink while program is running (advantage)
• has additional methods that are helpful (advantage)
• more flexibility and more dynamic (advantage)
• slower due to memory demands (disadvantage)

Question 6

How do we declare an Arraylist?

Answer 6

1) import jan package: import java.util.Array List;
2) ArrayList < Type> arrayName = new ArrayList < Type> ();

Question 7

How do we declare an Arraylist?

Answer 7

1) import jan package: import java.util.Array List;
2) ArrayList < Type> arrayName = new ArrayList < Type> ();

Question 8

What is Method Overloading?

Answer 8

When there are two or more methods within the same class that share the same name but different parameters

Question 9

What are methods?

Answer 9

• breaks code to smaller parts (advantage)
• easier to debug (advantage)
• more efficient and organized (advantage)
• can reuse code (advantage)
• best used to separate calculations, check data, etc

Question 10

What are the types of methods?

Answer 10

• Functional - return type - executes code, then returns a value
• Procedural - void type - executes code, but doesn’t return value

Question 11

Parts to a method

Answer 11

sum = getSum (num1 , num2); – argument
public static int getSum (int num1, int num2) { – modifiers, return type, method name, parameters

Question 12

What is scope of variables?

Answer 12

• part of program that variables can be accessed from
• variables can only be accessed from the block it’s in
• ex: variable in a method can be used throught method but not in other methods
• variables cannot be accessed before they are declared
• Local variables cannot be accessed outside of the method
• variables defined in a block can only be accessed within the block

Question 13

What is Pass by Value?

Answer 13

• When a copy of variable is sent to the method
• if value of variable is changed in the method there is no effect on the original copy, because they are discarded after exiting the method

Question 14

What is Pass by Reference?

Answer 14

• When a memory location of the value is sent to the method
• this changes the values of the reference because they are not copies
• ex: array

Question 15

Similarities and Differences between Bubble Sort and Improved

Answer 15

Bubble Sort: uses rested for loops , best case # of comparasions: n (n-1) / 2 , best case time: O (n^2)

Similarities: Worst case for # of comparisons: n (n-1) / 2, Worst case for time: O (n^2)

Improved: uses boolean variable, uses while condition, more efficient, Best # case: n- I, Best time case: O (n)

Question 16

Similarities and Differences between Bubble Sort and Improved

Answer 16

Bubble Sort: uses rested for loops , best case # of comparasions: n (n-1) / 2 , best case time: O (n^2)

Similarities: Worst case for # of comparisons: n (n-1) / 2, Worst case for time: O (n^2)

Improved: uses boolean variable, uses while condition, more efficient, Best # case: n- I, Best time case: O (n)