Types of Comments
A constant is a variable whose value can be assigned only once.
Constants are defined with a keyword let. If you know that the value of a variable will not change it should be declared as a constant.
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Syntax : let constantName = value
//
// main.swift
// Swift Tutorials 2014-15
// Constants in Swift
//
// Created by Code2care on 15/09/14.
// Copyright (c) 2014 Code2care. All rights reserved.
//
let contantVarable = 20
println("\(contantVarable)")
Output :
20
Program ended with exit code: 0
20
Program ended with exit code: 0
Note : If you try to reassign a value to a constant you would get an error! Cannot assign 'let' value 'contantVarable'
Constants Names :
You can assign any Unicode name to variable/constant names, this is not possible in many other porgramming languages. So you can use names from almost any language like German, Hindi, Chinese, Japanese e.t.c. You can even have a Smiley as a constant/variable name.Note that you cannot use arithmetic operators like + , - , * , % in a variable name, nor can the names start with a numeric value.
You can even define a variable name to a keyword that exists in Swift, just surround the name with back ticks (`) so that there is no conflict.
Output :
