New years resolution
In 2018 I will be back writing post here and I will try to be more consistent.
I will eventually go back to the subject of 'dynamic like' Java programming but just for fun I will start the year by looking at C++17 (including x14 and x11)
C++ is starting too look like a 21 century programming language so I think it is well worth looking at a few features that are starting to make programming really more productive.
WARNING: this is not a C++ style guide.
auto this, auto that
C++14 and 17 extend the power of auto and really make it more productive.
In C++11 they added the posibility of using auto for the return type of functions but you still had to provide the type using the new arrow syntax. In C++14 they completely removed the need to explicitly provide the type. Here is an example with both syntax:
class LazyCoder
{
public:
auto get_it_Cv11 () -> int
{
return 11;
}
auto get_it_Cv17 ()
{
return 17;
}
};
I don't think this is the best use of auto since the type in function declaration is also good documentation (better than comments).
In C++11 you could use auto for local variable declaration, for loop variables, function parameters.
With C++14 and C++17 you can now also use auto when declaring a variable in the scope of an 'if' and also when doing structured bindings (similar to other languages 'destructuring')
// Create a tuple
auto tuple = std::make_tuple(3, 7);
// C++14
int i, j;
std::tie(i,j) = tuple;
assert (i == 3 && j == 7);
// C++17 (look ma, no explicit variable declaration)
auto [x, y] = tuple;
assert (x == 3 && y == 7);
// and then ...
if (auto t = (x != y))
{
// I can use t here
cout << "This is getting ridiculous like t=" << t << endl;
}
C++z17 has one more trick up its sleeve. The 'structured binding' works with user data types.
// I have this struct defined somwhere
struct Zmas
{
int z, w;
};
// Now I can do this:
Zmas zmas {7, 11}; // Uniform intialization with curly brackets (next post)
// The number of items between square bracket here must match the number of public
// members of Zmas
auto [z, w] = zmas;
assert (z == 7 && w == 11);
Of course C++11 addition of auto was already a major improvement when working with complicated types but the latest extensions are even more icing on the cake.
For more details about auto check out
C++17 Structured Bindings
