Comp Sci Flashcards
How many bits in a byte
8
How many bits in a nibble
4
Files
a large group of bytes in auxiliary memory
What is the place called where files are stored
directories/folders
Which takes precedence in the ||: True or False
True takes precedence
Which takes precedence in the &&: True or False
False takes precedence
What does an enumeration do
lists the values a variable can have
int m = 4;
int results = 3 * (++m);
results = 15
int m = 4;
int results = 3 * (m++);
results = 12
What is encoding
translating from one set of symbols to another set of symbols (integer to binary)
What are the 8 primitive data types
int, double, char, Boolean, float, long, short, byte
What are 6 comparison operators
==, <=, >=, !=, <, >
What are the 3 logical operators
&&, ||, !
Lexicographic Order rules
all numbers come before letters and all uppercase letters come before lowercase letters
What is the Lexicographic Order based on
based on the character order in the Unicode character set
What is another word for conditional operator
ternary operator
When is a boolean expression a tautology
when the result is always true
When is a boolean expression a contradiction
when the result is always false
When is a boolean expression a contingency
when it is neither a tautology nor a contradiction
Tautology/Contradiction/Contingency?
(x == y) || (x != y)
tautology
Tautology/Contradiction/Contingency?
(x == y) && (x != y)
contradiction
Tautology/Contradiction/Contingency?
(x && y)
where both x and y = boolean values
contingency
general formula for encoding
ceiling(log2(n))
general formula for encoding in English
see how many times we can divide by 2 (starting at n) until we reach the quotient 0.
What are the 4 types of integer values
byte, int, short, long
What the 2 types of floating point numbers
float, double
What kind of value is a character
single character
What kind of value is a boolean
Boolean
how much memory does one byte use
1 byte
how much memory does one int or one float use
4 bytes
how much memory does one short or one char use
2 bytes
how much memory does one long or one double use
8 bytes
What does ASCII stand for
American Standard Code for Information Interchange
How many symbols does 7-bit ASCII contain
2^7 (128 symbols)
How many symbols does 8-bit ASCII contain
2^8 (256 symbols)
Java uses _________ for ____
16-bit Unicode, char
what are 2 ways floating-point constant can be written as
1, numbers after decimal place
2. e notation
In Java, you can’t store a floating-point number in a variable that is declared as an int because…
Java is said to be strongly typed
What is the data stored by a variable called
value
Which one is the assignment operator: = or ==?
=
RAM
random access memory
main memory is a type of ___________
volatile memory
auxiliary memory is also called…
secondary memory
what is a program
a finite sequence of instructions for a computer to follow written in a programming language
Following the instructions is called
running or
executing the program
What is a process
a program that is currently executing
What does the operating system do?
oversees the operation of the computer and its main job is to manage processes and hardware resources
do computers understand high-level languages like java?
no which is why computers have compilers
what do compilers do
they translate programs from high-level languages to low-level languages
Does the java compiler translate from java to machine language?
no, it translates it into java byte-code
What happens after the Java compiler translates the program to byte-code
the interpreter translates each byte-code instruction into machine language before it moves on to the next byte-code instruction
The class loader…
automatically connects different classes together in Java
What is a package
a library of classes that have already been defined
ex. java.util.Math;
what does a statement end with
a semicolon;
what are the grammar rules of code called
syntax
When printing to a screen (System.out.println()) which part is the object and which part is the method/function?
Object- System.out
Method/Function- println
What is the difference between the pre-compiled version and the byte-code version of a program
they have the same name, but the pre-compiled version ends in .java, while the byte-code version ends in .class
What are the 3 types of errors
- Syntax error
- Run-time error
- Logic/Semantic errors
What are syntax errors?
grammatical errors; they are shown with red squiggly line under code or smthg like that
What are runtime errors?
Errors that occur when you run a program (like dividing by zero or going Index Out of Bounds); the program usually terminates itself in times like this
What are logic/ semantic errors?
Errors that allow the program to run, but produce incorrect results like if you wanted a program that produces the sum of numbers but you accidentally put the formula as x - y. The program will still run, but it will give you the wrong value as the sum.
you got this
i bet i do
