An operator is a symbol or combination of symbols that we can use to check, change, or combine values. We have used operators in most of the examples so far in this book, but we did not specifically call them operators. In this section, we will show you how to use most of the basic operators that Swift supports.
Swift supports most standard C operators and also improves on some of them to eliminate several common coding errors. For example, the assignment operator does not return a value, which prevents it from being used where we are meant to use the equality operator (==).
Let's look at the operators in Swift.