Ch2. Data Types (zybooks)

Question 1

what is a variable ?

Answer 1

variable= named item that is used to hold a value.

Question 2

assignment statement?

Answer 2

assignment statement: is when a variable is assigned a value. this is done through a statement.

Question 3

what is the format of an assignment? hint: statements and variables

Answer 3

the left side of a statement assignment must be a variable while the right side can be an expression. so…
x = (y+5) X is the variable while (y+5) is the expression.

Question 4

what does

mean in programming ? how does it work

Answer 4

=
not equals but instead equals is used to assign a value from the right side to a left side variable.
so… x = 5 means x is assigned 5.

Question 5

what is an incrementing variable and how does it work.

Answer 5

increment variable: when a variable is assigned itself plus one. for example: x = x + 1

Question 6

variable declaration?

Answer 6

statement that declares a new variable -type and name.

Question 7

what is an assignment statement?

Answer 7

assignment statement:

Question 8

what is an assignment statement?

Answer 8

assignment statement:

assigns a variable (left side of = ) with the value to the right of =

Question 9

expression?

Answer 9

expression : a number, variable name or calculation

Question 10

what does ‘int’ stand for in code?

Answer 10

int = integer or a number.

it tells the memory to allocate a space for the following object. this object holds a number/integer

Question 11

can int variables (integer) hold a negative value?

Answer 11

yes, integer values can hold a negative value.

Question 12

what is a reserve word or keyword?

Answer 12

reserve word/ keyword: a word that is part of the language (int, sort, double,) these words can not be used as an identifier.

Question 13

how is an _ identified when used in an identifier?

Answer 13

_ is treated as a letter and can be the 1st “letter” in the identifier name.

Question 14

are spaces allowed in an identifier name?

Answer 14

no, but _ can be used instead.

Question 15

can an expression be a literal?

Answer 15

expression: evaluates to a value. a literal is a specific value. YES, an expression can be a series of operators (+ - ) with literals or variables or it can just be one literal.

Question 16

can two - - operators that are negative be next to one another?

Answer 16

• • Yes, seen as one a negative and a negation (negative of the following value)

Question 17

Precedence rules?

Answer 17

Precedence rules: how math symbols are used in a problem. order of operations..
() first,
-x negative numbers evaluated before multiplication
…use () often to make expressions clear and oreder of operations.

Question 18

compound operators?

Answer 18

when an operator is compounded for instance: numBalls = numBalls + 1
compounded into:
numBalls += 1

Question 19

are commands allowed in interger literals and if so how are they used?

Answer 19

no. integer intervals can not use commas.

Question 20

variable declared with ;double; means what?

Answer 20

is used to store a floating point number which is when a number has a decimal point within it

Question 21

what is a flouting point litera;?

Answer 21

floating point literal is a number that has a portion that is a fraction and is marked using decimal point with leading zero.

Question 22

how to do scientific notation for floating point literal?

Answer 22

the letter e is used to represent exponent. so 6.02 x 10^23 would be written as: 6.02e23

Question 23

what is the name of a variable that cannot change?

Answer 23

constant variable

if a variable is preceded with final variable then the variables value can not change after that statement.

Question 24

what is a good practicce with writing code when writing a constant variable? what format?

Answer 24

all uppercase letters and word have _ between them.

Question 25

Modulo operator?

Answer 25

Modulo operator = % when division occurs then this symbol tells what the remainer would be.
example: 23 % 10 = 3
see remainder of 3