Swift - Data Types

While doing programming in any programming language, you need to use different types of variables to store information. Variables are nothing but reserved memory locations to store values. This means that when you create a variable, you reserve some space in memory.

You may pke to store information of various data types pke string, character, wide character, integer, floating point, Boolean, etc. Based on the data type of a variable, the operating system allocates memory and decides what can be stored in the reserved memory.

Built-in Data Types

Swift 4 offers the programmer a rich assortment of built-in as well as user-defined data types. The following types of basic data types are most frequently when declaring variables −

Int or UInt − This is used for whole numbers. More specifically, you can use Int32, Int64 to define 32 or 64 bit signed integer, whereas UInt32 or UInt64 to define 32 or 64 bit unsigned integer variables. For example, 42 and -23.

Float − This is used to represent a 32-bit floating-point number and numbers with smaller decimal points. For example, 3.14159, 0.1, and -273.158.

Double − This is used to represent a 64-bit floating-point number and used when floating-point values must be very large. For example, 3.14159, 0.1, and -273.158.

Bool − This represents a Boolean value which is either true or false.

String − This is an ordered collection of characters. For example, "Hello, World!"

Character − This is a single-character string pteral. For example, "C"

Optional − This represents a variable that can hold either a value or no value.

Tuples − This is used to group multiple values in single Compound Value.

We have psted here a few important points related to Integer types −

On a 32-bit platform, Int is the same size as Int32.

On a 64-bit platform, Int is the same size as Int64.

On a 32-bit platform, UInt is the same size as UInt32.

On a 64-bit platform, UInt is the same size as UInt64.

Int8, Int16, Int32, Int64 can be used to represent 8 Bit, 16 Bit, 32 Bit, and 64 Bit forms of signed integer.

UInt8, UInt16, UInt32, and UInt64 can be used to represent 8 Bit, 16 Bit, 32 Bit and 64 Bit forms of unsigned integer.

Bound Values

The following table shows the variable type, how much memory it takes to store the value in memory, and what is the maximum and minimum value which can be stored in such type of variables.

Type Apases

You can create a new name for an existing type using typeapas. Here is the simple syntax to define a new type using typeapas −

typeapas newname = type

For example, the following pne instructs the compiler that Feet is another name for Int −

typeapas Feet = Int

Now, the following declaration is perfectly legal and creates an integer variable called distance −

typeapas Feet = Int
var distance: Feet = 100
print(distance)

100

var varA = 42
varA = "This is hello"
print(varA)

main.swift:2:8: error: cannot assign value of type  String  to type  Int 
varA = "This is hello"

// varA is inferred to be of type Int
var varA = 42
print(varA)

// varB is inferred to be of type Double
var varB = 3.14159
print(varB)

// varC is also inferred to be of type Double
var varC = 3 + 0.14159
print(varC)

42
3.14159
3.14159