In modern C++, the trailing return type syntax allows you to declare the return type of a function after the parameter list. This feature was introduced in C++11 to make it easier to specify the return type of functions that depend on template parameters or involve complex type deductions.

Syntax

The trailing return type syntax uses the auto keyword along with the -> operator to specify the return type after the parameter list. Here’s the general syntax:

auto functionName(parameterList) -> returnType {
    // Function body
}

Where functionName is the name of the function, parameterList is the list of function parameters, and returnType is the return type of the function.

Example

Consider a simple example of using trailing return type syntax with a function that returns the sum of two numbers:

auto add(int a, int b) -> int {
    return a + b;
}

In this example, add is the function name, (int a, int b) is the parameter list, and -> int specifies that the return type is int.

Benefits

Using trailing return type syntax can be particularly helpful when dealing with complex type deductions, such as when working with templates or functions that use decltype or trailing return type for deducing the return type.

Conclusion

The trailing return type syntax in C++ provides a more flexible and readable way to declare the return type of a function, especially in scenarios where the return type depends on complex type deductions. It is a powerful feature that enhances the expressiveness of C++ functions.

For more information on trailing return type syntax, refer to the C++ standard documentation.