Basic Programming Constructs – Scala

Private: HDP Certified Spark Developer (HDPCSD) – Scala Basics of programming using Scala Basic Programming Constructs – Scala

Let us understand basics of programming using Scala.

Declaring Variables
Basic Programming Constructs
Code Blocks

Declaring Variables

As part of this topic we will see details about declaring variables. We will also look at data types. To explore Scala you should primarily use your laptop or desktop.

We will use Scala REPL to explore variables in scala.

val or var (immutable vs. mutable)
- val is immutable
- var is mutable
Implicit data types or Type inference
Explicit data types
There is no distinction such as primitive types and classes for primitive types
In Scala all primitive types are nothing but classes. Complexity is hidden from developers.
Primitive types are better in performance compared to classes for primitive types
When you specify classes for primitive types in Scala, if the variable have to behave like primitive type Scala compiler will take care of it
Here are the basic data types

Byte	8-bit signed two’s complement integer (-2^7 to 2^7 – 1, inclusive)
Short	16-bit signed two’s complement integer (-2^15 to 2^15 – 1, inclusive)
Int	32-bit signed two’s complement integer (-2^31 to 2^31 – 1, inclusive)
Long	64-bit signed two’s complement integer (-2^63 to 2^63 – 1, inclusive)
Char	16-bit unsigned Unicode character (0 to 2^16 – 1, inclusive)
String	a sequence of Chars
Float	32-bit IEEE 754 single-precision float
Double	64-bit IEEE 754 double-precision float
Boolean	true or false

Task

create val a that is an integer value 42
create val b that is a long value 42
create val c that is a float value 42.0
create val d that is a double value as multiplication of a, b, c
create val e that is a short value 42.0
create val f that is a byte value 42.0
create val g that is a hex of number (42) in base 10

Basic Programming Constructs

As part of this topic we will see core language constructs.

Let us see basic programming constructs, such as if else, while loop, for loop etc. As any programming language, Scala also support

if condition
ternary operator
while loop
for loop
Arithmetic operations
Boolean operations
and more

However we do not use for loop as extensively while dealing with collections, we will see it later.

Task 1 – Factorial

Develop a program which will print factorial of a given number

Task 2 – Fibonacci

Develop a program which will generate number of elements in a Fibonacci series

Code Blocks

As part of this topic we will see fundamental of programming – Code blocks

Any thing that comes in the middle of { } is considered to be block of code
A block of code can be assigned to a variable. Code will be evaluated first and then the value will be returned to variable
It can also be assigned to functions – next topic
Blocks can be nested
Each line of code need not be ended with ; as in java. ; is optional
But if you want to write more than one expression in one line then each expression should be ended with ;
In blocks, the last statement of the code-block becomes the return value

Expression vs. Statement

Expressions are some code that yields a result. You can also say that an expression evaluates to a result or results in a value.
Statements are some code that does some action. This action is also called as a side effect. They do not return anything.
In scala, many constructs like code-blocks, if-else, method bodies are expressions
Expressions always return a value.
The value of c in the below code snippet from gist is the value of i – j
The type of the last statement becomes the type of the target variable
Data type of sqr in the below code snippet from gist is boolean

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