Test 3 Flashcards
What does it mean to decrement a variable?
Subtract 1 from it
What does it mean to increment a variable?
Add 1 to it
What is a unary operator?
An operator with a single operand
What does x++; mean?
Add 1 to x
What does x–; mean?
Subtract 1 from x
What is a binary operator?
An operator with 2 operands
What does x+=5; mean?
Add 5 to x
What’s does x-=5
Subtract 5 from x
What does x*=5; mean?
Multiply x by 5
What does x /=5 mean?
Divide x by 5
What’s shorthand for x=x+23
x+=23 (etc for other operations)
What data type is used to process individual characters?
char
What data type is used to process one or more characters
String
What kind of quotes used w/ String
Double “”
What kind of quotes used with characters
Single ‘’
What is accomplished by the statement c1=c2=c3=’Q’; what type of assignment is this called?
Every variable is assigned to the value of Q, chain assignment or chaining
Why is + an overloaded operator
It concatenates (with String variables) and adds (with int or double)
Who invented form of algebra based on logic statements that are either TRUE or FALSE
George Boole
What data type can only store either TRU or false
Boolean
What is datas formal language for the term simple data types
Primitive data types
Code for assigning 2.7 as a CONSTANT for the value of E?
final double E = 2.7
What happens when you attempt to alter the value of a constant?
Compile error
What is the 1st form of program documentation?
To use comments
Why did older programs 1960/70s use single-letter variables?
Memory scarce and expensive, save every byte possible
Self-commenting variable
A variable whose name describes what it’s used for (heightInches = 54)
Instead of single-letter variables, nowadays variables should be…
Words or compound words
In a well-documented programs, single line comments or multi line comments necessary?
Yaaa
Does Java follow PEMDAS
Yupp
How do u find square root?
Math.sqrt(x);
How do u round?
Math.round(x)
How do u round up?
Math.ceil(x);
How round down?
Math.floor(x)
How do u find max over min?
Math.max(x,y);
How find absolute value?
Math.abs(x)
How find power?
Math.pow(x,y)
How times Pi?
Math.PI(x)
Java source code file extension?
.java
Float
decimals (7 places)
Single line comments
Forward slashes // aka inline comments, provide brief summary comments for chunks of code
Multi-line comments
Start with /* end with */
Backslash \ + what makes a new line, backspace, horizontal tab, backslash, single and double quote?
\n, \b, \t, \, ', "
Identifier
Name given to package, class, method, or variable (allows programmer to refer to item from other places in program)
Variables can only have…
Letters, __, or $
Use lowercase first “appleBanana” unless it’s a final/constant
No reserved words
Reserved/keywords are
Lowercase, NOT used as methods or variables
A program with 1 or more compile errors?
Can compile, but will stop executing at point of compile error
The “print” keyword…
Displays text output to monitor w/o carriage return (doesn’t go to next line but “ln” does)
Compiled files have the extension…
.class
When dividing ints as opposed to doubles…
It takes the integer, so 4/5 is 0.8 but if it was an int it would be 0
Finding modulus (remainder)
If q%=25, and q=14, it’s 14%25 which is 14/25 and 14 is in the house
Reserved words include
public void static double int if byte boolean package else class for return
Powers of 2 wen converting??
2 to the 0, 2 to the 1, 2 to the 2….2
to the 7
