Ch2. Data Types (zybooks) Flashcards
what is a variable ?
variable= named item that is used to hold a value.
assignment statement?
assignment statement: is when a variable is assigned a value. this is done through a statement.
what is the format of an assignment? hint: statements and variables
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.
what does
mean in programming ? how does it work
=
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.
what is an incrementing variable and how does it work.
increment variable: when a variable is assigned itself plus one. for example: x = x + 1
variable declaration?
statement that declares a new variable -type and name.
what is an assignment statement?
assignment statement:
what is an assignment statement?
assignment statement:
assigns a variable (left side of = ) with the value to the right of =
expression?
expression : a number, variable name or calculation
what does ‘int’ stand for in code?
int = integer or a number.
it tells the memory to allocate a space for the following object. this object holds a number/integer
can int variables (integer) hold a negative value?
yes, integer values can hold a negative value.
what is a reserve word or keyword?
reserve word/ keyword: a word that is part of the language (int, sort, double,) these words can not be used as an identifier.
how is an _ identified when used in an identifier?
_ is treated as a letter and can be the 1st “letter” in the identifier name.
are spaces allowed in an identifier name?
no, but _ can be used instead.
can an expression be a literal?
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.
can two - - operators that are negative be next to one another?
- Yes, seen as one a negative and a negation (negative of the following value)
Precedence rules?
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.
compound operators?
when an operator is compounded for instance: numBalls = numBalls + 1
compounded into:
numBalls += 1
are commands allowed in interger literals and if so how are they used?
no. integer intervals can not use commas.
variable declared with ;double; means what?
is used to store a floating point number which is when a number has a decimal point within it
what is a flouting point litera;?
floating point literal is a number that has a portion that is a fraction and is marked using decimal point with leading zero.
how to do scientific notation for floating point literal?
the letter e is used to represent exponent. so 6.02 x 10^23 would be written as: 6.02e23
what is the name of a variable that cannot change?
constant variable
if a variable is preceded with final variable then the variables value can not change after that statement.
what is a good practicce with writing code when writing a constant variable? what format?
all uppercase letters and word have _ between them.
Modulo operator?
Modulo operator = % when division occurs then this symbol tells what the remainer would be.
example: 23 % 10 = 3
see remainder of 3
