Defining Function and Class Templates

In the previous section, we saw the advantages of templates in writing abstractions. In this section, we are going to explore how we can effectively use templates in our code to create templated functions and templated classes.

Function Template

In the previous section, we learned how function templates are written.

In this section, we will learn about the two features that were introduced by C++11 that make it easier to write template functions. These two functions are trailing return types and decltype.

Let's start with the decltype. The decltype is a keyword that accepts an expression and returns the type of that expression. Let's examine the following code:

int x;
decltype(x) y;

In the previous code, y is declared as an integer, because we are using the type of the expression x, which is int.

Any expression can be used inside decltype, even complex ones, for example:

User user;
decltype(user.getAccount()) account;

Let's look at the second feature—trailing...