Functions may be written to run a routine and not return a value. If this is the case, you must specify that the function returns void. In most cases, a function will return a value, if only to indicate that the function has completed correctly. There is no requirement that the calling function obtains the return value or does anything with it. The calling function can simply ignore the return value.
There are two ways to specify the return type. The first way is to give the type before the function name. This is the method used in most of the examples so far. The second way is called the trailing return type and requires that you place auto as the return type before the function name and use the -> syntax to give ...
