U3: Predefined Methods

Question 1

Method [A]

Answer 1

• Has own name
• Action already written
• Stored in separate file “class” having name

Question 2

Method [B]

Answer 2

• Needs info to be sent
• Can return data to main program
• Can be executed from main program

Question 3

Passing Arguments

Answer 3

Information sent to a method

Question 4

Outputting Math Methods

Answer 4

System.outprintln(Math.method(num1, num2))

Question 5

max

Answer 5

• Maximum of two numbers
• int num1 = 34; int num2 = 12;
• Output: 34

Question 6

min

Answer 6

• Minimum of two numbers
• int num1 = 34; int num2 = 12;
• Output: 12

Question 7

pow

Answer 7

• First input to power of 2nd
• int num1 = 2; int num2 = 6;
• Output: 64

Question 8

abs

Answer 8

• Absolute value
• double num = -34.214;
• Output: 34.214

Question 9

hypot

Answer 9

• (num1^2 + num2^2)^½:
• int sideA = 4; int sideB = 3;
• Output: 5

Question 10

ceil

Answer 10

• Rounded up nearest integer
• double num = 82.114;
• Output. 82.0

Question 11

floor

Answer 11

• Rounded down nearest integer
• double num = 87.876
• Output: 87.0

Question 12

sqrt

Answer 12

• Square root of number
• double num = 64;
• Output: 8.0

Question 13

round

Answer 13

• Rounded to nearest integer
• double num = 64.545
• Output: 65

Question 14

random

Answer 14

• Positive double value between 0.0 and 1.0
• System.out.println(Math.random());
• Possible Output: 0.1311034762657053

Question 15

toDegrees

Answer 15

• Angle in radians to degrees
• double angle1 = 0.7853981633974483;
• Output: 45

Question 16

toRadians

Answer 16

• Angle in degrees to radians
• double angle1 = 45;
• Output: 0.7853981633974483

Question 17

sin

Answer 17

• Sine for angle
• double angle1 = 45;
• Output: 0.649448048

Question 18

cos

Answer 18

• Cosine for angle
• double angle1 = 45;
• Output: 0.760405965

Question 19

External Class

Answer 19

Separate area from main program that contains methods program uses

Question 20

tan

Answer 20

• Tangent for angle
• double angle1 = 45;
• Output: 0.854080685

Question 21

Passing Arguments

Answer 21

“Passing” data from main program to method

Question 22

Arguments

Answer 22

• Variables passed in method call
• Inside brackets after name of method

Question 23

Types of Arguments

Answer 23

Integers, Doubles, etc

Question 24

Parameters

Answer 24

• Defined in method definition
• Appear when writing actual method

Question 25

words.[starts/ends]With(“string”)

Answer 25

Returns boolean value if string starts/ends with specific word

Question 26

Method Call

Answer 26

The use of a method to pass data

Question 27

Finding Location of Character

Answer 27

• Location stated as integers; starts at 0
• Ex: p of “Computer”: 3

Question 28

words.charAt(integer)

Answer 28

Returns character located at integer position in string

Question 29

words.toUpper()

Answer 29

Converts string to all uppercase

Question 30

words.toLower()

Answer 30

Converts string to all lowercase

Question 31

[variable].replace(“oldChars”, “newChars”)

Answer 31

Replaces character/set of characters in string with new characters/set of characters

Question 32

[variable].length()

Answer 32

Returns no. of characters in string

Question 33

[variable].lastIndexOf(“string”)

Answer 33

Outputs location where stated characters are last found

Question 34

[variable].indexOf(“string”)

Answer 34

• Returns integer where stated characters are first found in string
• Returns -1 if not found