Flashcards in Unit 1 - CH 2 Deck (45):
1
Define Variable
A location in memory that contains one or more data values
2
Define Identifier
A unique name given to a variable, procedure, or function, etc
3
Define High-level programming language
A language that has English-like keywords and commands to express the basic constructs of sequence, selection, and iteration
4
Define Integer Division
A process that returns only the whole number section of a division.
E.g. 7/2 = 3.5 but integer division would return 3
5
Define Compiler
A program that translates source code into executable object code
6
Define Console Application
A program that runs on a text-based window into which the user types and which displays text output from the computer
7
C# Integer Division
int wholeNumberPart = num1 / num2
8
C# modulo operation
int remainder = num1 % num2
9
C# commenting
Single line
// comment
Multi line
/* comments */
10
C# user input
string input = Console.Readline ()
11
C# display/output
Display and leave cursor on same line
Console.Write ("Heya")
Display and move cursor to newline
Console.WriteLine ("Coolio")
12
C# string formatting layout
Console.WriteLine("{0} plus {1} is {2}", num1, num2, sum);
13
Define Global variable
A variable declared at the beginning of a program and accessible from anywhere in the program.
Not always desirable as its values 0may be accidentally changed
14
Define Local variable
A variable declared in a program block and only accessible within the scope of that routine.
15
Define Constant
A variable whose value does not change throughout the program runtime
16
What is the difference between an integer and a real number?
Integers are whole numbers, real numbers can have a fractional part/decimal point.
17
Why use int instead of real?
They use less memory and store values accurately.
18
Define string
A sequence of zero or more characters
19
Define character
Any letter, number, or symbol in a character set such as ASCII
20
C# string accessing
charThree = aString [4]
Zero-indexed
21
C# dateTime usage
dateTime today;
today = DateTime.Today;
dateTime tomorrow = today.AddDays (1);
dateTime anniversary = System.Convert.ToDateTime ("08/09/2017");
22
Define Record
A data structure that groups a number of variables.
Lightweight classes, basically.
23
What data structure is this?
struct Book
{
public string Title, ISBN;
public decimal Price;
public int PublicationYear;
}
Book theMazeRunner;
theMazeRunner.Title = "The Maze Runner"
Defining and then initializing a record in C#
24
Define Enumerated type
An ordered set of values
25
Define Field
A variable that is part of a record
26
Define Set
A collection of values of the same ordinal type with no associated order.
27
What are the 4 set operators?
1. Union (set3 = set1 + set2): values from both sets minus duplicates
2. Difference (set3 = set1 - set2): all set1 values that are not in set2
3. Intersection (set3 = set1 * set2): only values found in both sets
4. Membership (if a in set1 then): tests whether a value is in a set
28
What are the 4 logical bitwise operators?
NOT
AND
OR
XOR
29
What are the 3 Boolean operators?
AND
NOT
OR
30
What are the relational operators?
==
<
>
!=
<=
>=
31
C# nested IF statement
if (condition){ }
else if (alternate condition){ }
else{ }
32
C# switch case statement
switch (x){
case 4:
z += 1;
break;
case 5:
z -= 1;
Console.Write (x);
break;
}
33
Difference between nested IF statements and switch case statements?
IF statements are executed when a condition is met (e.g. x > 5)
Case statements are executed when a variable x has a specific value (e.g. case 6)
34
C# for loop
for (int count=1; count <5; count++)
{
Console.WriteLine (count)
}
Used when the number of iterations is known and finite
35
C# foreach loop
foreach (name in namesList)
{
Console.WriteLine(name);
}
Good for inspecting every element in an array
36
C# do while loop
do
{
Console.Write ("Your name: ");
name = Console.ReadLine ();
}
while (name != "Ash");
37
What is the difference between passing parameters by reference and passing by value?
Calling by reference:
Passes a reference to the memory location of the variable to another procedure. Anything done to the variable in this procedure will also change it's value elsewhere.
Calling by value:
A copy of the variable is passed to the called procedure and anything done to it has no effect outside the procedure scope.
38
C# one dimensional array
string[ ] arrayName = {"I'm", "an", "array"};
arrayName [0] = "I am";
Console.Write(arrayName [0], arrayName [2]);
OUTPUT:: I am array
39
C# two dimensional array
int [ , ] arrayName = new int [4,4]
arrayName [0,3] = 123
#Accesses first row, fourth column
40
In C#, array elements have to be of the same datatype. Parallel arrays of different datatypes are inefficient; how do you go around this?
Create an array of records (custom datatype struct)
recordDataType [ ] arrayName = new recordDataType[5]
arrayName [0].recordField1 = value
41
What's a CSV file?
Comma Separated Values file.
Text file with one record per line, and record fields separated by commas.
Used as data files for mail-merge programs.
42
What's a Binary file?
A file of records, usually containing multiple datatypes. Datatypes other than strings and chars are stored in internal format and can't be displayed in a meaningful way in a text editor (which only interprets ASCII or Unicode character codes).
43
What's a Text file?
A sequence of printable characters organised line by line, which can be accessed and read in a text editor.
44
C# Writing to a text file
static StreamWriter currentFileWriter;
static void Main(string [ ] args)
{
string fileName = "filename.txt";
currentFileWriter = new StreamWriter(fileName);
currentFileWriter.WriteLine("Hello World");
currentFileWriter.Close ()
}
45