Methods

Question 1

Write the General Structure of a Method

Answer 1

public static returntype methodname (zero or more input variables){
* // create local variables
* // do math ao logic
* // return result based on returntype (if applicable)
}

Question 2

Function of “methodname” in General Structure

public static returntype methodname (zero or more input variables){
* // create local variables
* // do math ao logic
* // return result based on returntype (if applicable)
}

Answer 2

give a name to method
* use this name in main program to ‘call’ the method

Question 3

Function of “zero or more input variables” in General Structure

public static returntype methodname (zero or more input variables){
* // create local variables
* // do math ao logic
* // return result based on returntype (if applicable)
}

Answer 3

take data in through input variables

• Note: variable names in main program do not have to match names in method
• Note: if there are no input values, leave ( ) blank when calling method.
• Note: the input variables do not have to match the returntype/output

Question 4

Function of “returntype” in General Structure

public static returntype methodname (zero or more input variables){
* // create local variables
* // do math ao logic
* // return result based on returntype (if applicable)
}

Answer 4

specifies type of data being output by the method

Question 5

Examples of ReturnTypes…

Answer 5

String
int
double
boolean
void (a.k.a. nothing)
long
char

Question 6

Explain Boolean

Answer 6

a variable type which holds the values: true or false
- has no quotations

Question 7

What word is “char” short for?

Answer 7

character

Question 8

Special features of Char variables

Answer 8

can use math comparison symbols on them

Question 9

Function of:

strWord.charAt(integer#)

Answer 9

take the single character with the index/subscript of the number in () from a given string

Question 10

Write the line of code which takes a single letter in a string USING CHAR VARIABLES.

Answer 10

chrLetter = strWord.charAt(integer#);

Question 11

Type of quotations used by char variables

Answer 11

single quotations

Question 12

Type of quotations used by String variables

Answer 12

double quotations

Question 13

Function of return keyword

Answer 13

returns a value back to main program

Question 14

Which return type does not need a return keyword?

Answer 14

return type: void

Question 15

Do local variables in methods exist in the main method?

Answer 15

No

Question 16

Write code to call a method in a different file (eg. allisontools file)

Answer 16

allisontools.methodname(input variables);

Question 17

Benefits of Methods

Answer 17

• main programs are shorter
• more efficient – you do not need to rewrite the same lines of code (math/logic) over and over again
• reduces the number of errors – you can write parts of the program at a time and test as you go
• easier collaboration/teamwork – different team members can work on different methods
• money: tool files can be so useful that you can sell them for a price

Question 18

Methods

Answer 18

pieces of code which programmers can access over and over again when its functionality is needed

Question 19

When do methods run?

Answer 19

when placed in main method & given proper input

Question 20

Alternate Names for Methods

Answer 20

Methods
Functions
Procedures

Question 21

Long Variable Type

Answer 21

integers that can hold numbers larger than 2 billion

Question 22

integer variable data that can hold numbers larger than 2 billion

Answer 22

Function of Long Variables

Question 23

Why use int when you have long?

Answer 23

to save RAM

Question 24

Where must tools files be located

Answer 24

in same folder as the programs which use it

Question 25

Implement a method `double sphereVolume(double r)` that calculates and returns the volume of a sphere given its radius r. Use the formula: V = (4/3) × π × r³. Test this method in a program.

Question 26

Write a method `boolean isLeapYear(int year)` that returns `true` if the given year is a leap year, otherwise `false`. Use the formula: A year is a leap year if it is divisible by 4 but not divisible by 100, unless it is also divisible by 400. Test this method in a program.

Question 27

Create a method `int charFrequency(String text, char c)` that counts and returns the number of times a character c appears in the given string text. Write a program to test this method.

Question 28

Define a method `int countVowels(String word)` that counts and returns the number of vowels (a, e, i, o, u) in the given string. Write a program to test this method. | USING CHAR