"Always Use Auto" in C++11? [closed]

Question

C++ guru Herb Sutter proposes that we should almost always use "auto". He states this on his website and he recently repeated it at the CppCon 2014 conference.

I've tried to follow his advice and I'm not convinced. Is there someone here who agrees with Sutter and who can tell me why

auto gender = string{};
auto number = string{};
auto person = string{};

is better than

string gender, number, person;

which is what I ended up writing in my code, because I couldn't bear the auto style.

Edit:

auto gender = string{}, number = string{}, person = string{};

is also a possibility, but in my opinion that's even worse.

Answer 1

The auto keyword should mainly be used in cases where you initialize the variable with a value, as this makes the code more maintainable in cases where you change the value you initialize the variable with:

uint16_t id_ = 65535;

uint16_t id()
{
    return id_;
}

auto myid = id();

No need to change the type of myid if id() return type changes.

And with C++14 it gets even better:

uint16_t id_ = 65535;

decltype(auto) id()
{
    return id_;
}

auto myid = id();

Changing the type of id_ automatically adjusts the return type of id() and the type of myid.

In cases where the initial value of the variable is not initialized with a value and as such is not dependent on other code for initialization, it makes sense to explicitly define the variable type, as the auto keyword would not add more maintainability to the code and the syntax auto gender = string{}; is less readable than string gender;.