In today's article, we'll be looking at the concept of Constants in Swift. I have already posted an article on Variables in Swift. Check it out . here Just like variables, the concept of constants is also very easy to understand and implement. Let's dive deeper and understand constants in-depth: What are constants? Just like its name, constants remain constant throughout the program! Once a value is declared as a constant in the memory, it cannot be changed throughout the execution of the program. How to initialize a constant? To declare a constant, we use the keyword, followed by the name we want to give to that particular constant and assign it to any kind of data type we want to be constant throughout the execution of the program. let It's just like initializing a variable but replacing the with the keyword. var let We can store any kind of data type as a constant, whether it may be an integer, float, double, string, boolean, etc. Let's look at an example: let myName = "Ishaan" According to this code snippet, we declare a new constant called myName that stores the string . ' Ishaan' Do remember to use the keyword , otherwise, your program will generate an error. let Now, myName, a constant has a value of 'Ishaan' in the memory, which will remain constant throughout the flow of our program. You may try implementing this on your own on a Swift Playground or some other compiler and explore new concepts and errors. Now, if we try to change the value of the constant , Swift will show us an error, as shown in the image below: myName In the second attempt of initialization, Swift throws an error that it cannot assign to a new value as it is a constant. myName It also shows us a hint to solve this problem by replacing with . In other words, it's asking us to declare myName as a variable if we need to change its value at any point of time, later in the program. let var Some examples with other data types: let isAdult = true print(isAdult) In this example, we store a boolean value as a constant in and then we print it. As expected, we will get as the output. isAdult true let myNumber = 13 print(myNumber) In this example, we store an integral value of 13 as a constant in and then we print it. As expected, we will get as the output. myNumber 13 let mathScore = 98.5 print(mathScore) In this example, we store a floating value of 98.5 as a constant in and then we print it. As expected, we will get as the output. mathScore 98.5 Good to know: Just like a variable, we can also explicitly declare a constant's data type to define what kind of data we want it to store in it. let mathScore:Int mathScore = 100 print(mathScore) Here, we are explicitly telling the compiler to make sure that the constant mathScore stores an integer value only, though only one time we'll be doing it (anywhere in the program). You may avoid explicitly declaring data type unless it's absolutely necessary. So that's all for this article. You now have a deep understanding of constants in Swift. I hope you have understood what I wanted to convey. Thank you for reading this. Previously published . here
