W2 - Data Types

Question 1

What are Data types?

Answer 1

Describes format and size of (i.e. memory occupied) a data item and defines what types of operation can be performed with that item.

Question 2

What are the types of Data types?

Answer 2

Native and Custom data types.

Question 3

What does Console.ReadLine() do?

Answer 3

It accepts user input

Question 4

What is Int type?

Answer 4

This produces a whole number and it’s signed 32-bit integer (int32)

Question 5

What is Char type?

Answer 5

This is a 16-bit numeric value. A char literal is delimited by a pair of single quotes (‘’).

Question 6

What is Double type?

Answer 6

Doubles can have a functional part and it’s defined as a 64-bit floating point value.

Question 7

What is a Decimal type?

Answer 7

A fixed precision number. Uses 128bit storage.

Question 8

What is a variable in C#

Answer 8

A variable is a storage location in memory with a specific data type that holds a value.

Question 9

What are the basic data types in C#?

Answer 9

The basic data types include:

int: Integer values.
double: Floating-point numbers.
char: Single characters.
string: A sequence of characters.
bool: Boolean values (true or false).

Question 10

How do you declare a variable in C#?

Answer 10

A variable is declared by specifying the data type followed by the variable name (e.g., int age;).

Question 11

What is an assignment statement in C#?

Answer 11

An assignment statement assigns a value to a variable (e.g., age = 25;).

Question 12

What are constants in C#?

Answer 12

Constants are variables whose values cannot be changed once assigned. They are declared using the const keyword (e.g., const int DAYS_IN_WEEK = 7;).

Question 13

How do you output data to the console in C#?

Answer 13

The Console.WriteLine() method is used to display text or variables in the console (e.g., Console.WriteLine(“Hello, World!”);).

Question 14

How do you read input from the user in C#?

Answer 14

The Console.ReadLine() method is used to read input from the user as a string (e.g., string input = Console.ReadLine();).

Question 15

What is type casting in C#?

Answer 15

Type casting is converting a variable from one data type to another. This can be implicit (automatic) or explicit (manual using a cast).

Question 16

What is the difference between implicit and explicit casting?

Answer 16

Implicit casting: Automatically converts smaller types to larger types (e.g., int to double).
Explicit casting: Requires manual conversion, usually with a cast operator (e.g., (int) or Convert.ToInt32()).

Question 17

What is string concatenation in C#?

Answer 17

String concatenation is combining two or more strings using the + operator (e.g., string fullName = firstName + “ “ + lastName;).

Question 18

What are escape sequences in C#?

Answer 18

Escape sequences are special characters in strings used for formatting, like \n for a new line or " for a quotation mark.

Question 19

What is the purpose of comments in C#?

Answer 19

Comments are used to add explanatory notes in code and are ignored by the compiler. Single-line comments use //, and multi-line comments use /* */.

Question 20

What is the difference between WriteLine() and Write() in C#?

Answer 20

Console.WriteLine() writes a line of output and moves to the next line, while Console.Write() writes output without moving to the next line.

Question 21

What is the Convert class in C# used for?

Answer 21

The Convert class provides methods to convert data from one type to another (e.g., Convert.ToInt32() to convert a string to an integer).

Question 22

What are arithmetic operators in C#?

Answer 22

Arithmetic operators include + (addition), - (subtraction), * (multiplication), / (division), and % (modulus for remainder).

Question 23

What is the modulus operator (%) used for in C#?

Answer 23

The modulus operator returns the remainder of a division operation (e.g., 7 % 2 returns 1).

Question 24

How do you format output in C#?

Answer 24

You can use placeholders with Console.WriteLine() to format output, such as Console.WriteLine(“The result is {0}”, result);.

Question 25

What are the rules for naming variables in C#?

Answer 25

Variable names must start with a letter, cannot contain spaces, and are case-sensitive. They should be meaningful and follow camelCase or PascalCase conventions.

Question 26

What is the Parse() method used for in C#?

Answer 26

The Parse() method is used to convert strings to numeric types, such as int.Parse() or double.Parse().

Question 27

What is the difference between Parse() and TryParse()?

Answer 27

Parse() throws an exception if conversion fails, while TryParse() returns false if conversion is unsuccessful, preventing errors.