Declaration
We must define constants in Swift before using them in our programme. We can declare constants using the "let" keyword in a swift programming language.
The syntax for declaring a constant is as follows:
Let constant_name = <Intial value>
For example,
let msg = "Welcome to Coding Ninjas."
print(msg)
The first line of the following code notifies the compiler that we defined a constant with the name "msg" and assigned its value; as a result, the compiler will allocate the necessary space in our computer memory to keep the constant value. The second line prints the value of the"msg" constant.
The output of the above code is as follows:
Welcome to Coding Ninjas.
We can declare multiple constants on a single line separated by commas.
Type Annotations
We can quickly determine what kind of values the constant can store in Swift by defining type annotation while declaring it.
We can define constant type annotation by following the constant name with a colon, a space, and the type's name.
The syntax for adding a type annotation to a constant in the Swift programming language is as follows:
let constant_name: <data type> = <Initial value>
Here's a simple example of applying a type annotation to a constant.
let msg: String = "Welcome to Coding Ninjas."
print(msg)
In the preceding example, we defined the constant "msg" and its data type (String). The swift programme above will return the value given below.
Welcome to Coding Ninjas.
When we declare a constant with a type annotation, we must specify that the constant's initial value matches its data type.
With a single type annotation following the last variable name, we can specify numerous related variables of the same type on a single line, separated by commas:
var python, java, csharp: String
Naming Constants
Constant names can contain nearly any character, including strings, numerals, underscores, and Unicode characters, but they should not contain whitespace, mathematical symbols, arrows, or incorrect code points.
The constant name should not begin with a number. However, numbers may appear elsewhere in the name. The following is a simple example of naming constants in Swift.
let exm12 = "Hello!!"
print(exm12)
let _example = "Ninja"
print(_example)
The result of the above code will be:
Hello!!
Ninja
Constants Concatenation and Interpolation
In Swift, we can combine two constants to form a single constant in two ways:
- By Concatenation
- By Interpolation
Following is an example of concatenating two constants into a single constant:
let str1 = "Hello!!"
let str2 = "Ninja"
Let result = str1 + str2
print(result)
The output of the above program is shown below:
Hello!! Ninja
We'll see how to utilise interpolation to mix two constants with examples. In Swift, here's a simple example of mixing two constants using interpolation.
let str1 = "Hello!!"
let str2 = "Ninja"
print(" / (str1) / (str2)" )
The output of the above program is shown below:
Hello!! Ninja
Printing Constants
The "print" function in Swift can be used to print constants. A basic example of printing constants follows.
let str1 = "Printing"
let str2 = "Constants."
Let result = str1 + str2
print(result)
The output of the above program is shown below:
Printing Constants.
Based on our needs, this is how we can define, declare, and use constants in a swift programming language.
Frequently Asked Questions
What exactly is a named constant?
A constant can be given a name. This name signifies a specific value that cannot be modified when the application is running. The precision of numeric named constants is undefined.
What are the benefits of naming constants?
The role of a named constant is indicated by its name. The benefit of utilising named constants is that if the supplied value is changed in the source code, it is only needed to change the declaration statement rather than looking up all of the value's occurrences.
What is Swift suitable for?
Swift is an Apple-developed programming language for developing iOS, Mac, Apple TV, and Apple Watch programs. It's intended to allow developers more flexibility than ever before. Swift is simple to use and open-source, allowing anyone with an idea to make something unique.
Is Swift a front-end or a back-end language?
Both are correct. Swift can be used to create client-side (frontend) and server-side (backend) software.
Conclusion
This article extensively discussed Swift Constants, their declaration, how to name them, Concatenation and Interpolation of Constants, and printing their results with examples. Check out the definitive swift tutorial for beginners to know more about Swift.
We hope this blog has helped you enhance your knowledge regarding constants in Swift. You can learn more about IOS by visiting the Ios and os related articles in CodingNInjas Blogs.
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