[KayEss]

C++ ends up with three forms (of course it does):

Normal C style declaration

    int foo() { return 2; }

Trailing return type. Useful when the return type depends on the parameter types, or is inside the namespace of the function

    auto foo() -> int { return 2; }

Automated type deduction. Increasingly the choice when possible

    auto foo() { return 2; }