Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror

Comment: Re:Not a new idea (Score 2) 27

by Rei (#49795303) Attached to: GoPro's Next Adventure: Virtual Reality and Drones

I figured they'd tackle something more ambitious than that with their drone offerings - a drone that (barring instructions to do otherwise) follows you around whatever you're doing and keeps the camera on you, trying to get the most epic shots. E.g., you bungee jump off a bridge, it races you to the bottom, keeping whatever distance and filming style you told it to.

But maybe it's just another remote control drone.

Comment: Re:Terraforming potential? (Score 1) 272

by Rei (#49792059) Attached to: How To Die On Mars

But that's the point. If it slams into an immobile object of course. But we're not talking about anything slamming into an immobile object. From the perspective of a molecule in the gas stream, it's going about the same speed as its neighbors. It's quite cool.

As for the boundary region, even at the "pinched" funnel outlet one could be talking dozens of kilometers here. A dozen kilometers between going from zero velocity and 25 kilometers per second is roughly the same as a dozen meters between going from zero velocity and 25 meters per second. Aka, a virtually insignificant gradient.

Comment: Re:I am amazed (Score 1) 242

by Rei (#49789327) Attached to: A Text Message Can Crash An iPhone and Force It To Reboot

I like that idea. You're right, it should be pretty efficient to implement, regardless of the string's backend encoding. And the value represented by the iterator will, by nature of being implemented as a pointer to a certain part in the string, be able to point to a glyph of arbitrary length (unlike a getter function with a fixed-length return type). Being an iterator it'll fit into all standard c++ libraries that take iterators.

It would be nice to have it be a random-access iterator so that you can jump to an arbitrary offset. There's a lot of optimizations they could do internally to help facilitate that. But obviously you still want to let programmers choose - by some means or another - whether they want such unicode optimizations (or unicode iteration, or so forth). Because while the overhead they'd impose wouldn't be huge, there still would be overhead.

Comment: Re:Terraforming potential? (Score 1) 272

by Rei (#49789303) Attached to: How To Die On Mars

Except wait - we've got a phase change from gas to plasma in there, which almost certainly breaks their calculations badly.

Again, no, you don't. All of the particles are moving in the same direction. They're not hot. They're not slamming into each other and kicking electrons off.

Do you think if you had a spacecraft moving at 25.4 kilometers per second it would be plasma too?

Comment: Re:Terraforming potential? (Score 1) 272

by Rei (#49785427) Attached to: How To Die On Mars

First off, you're misusing temperature. You don't call it heat if all of the particles are moving in the same direction and unionized, you just call it "wind". It only becomes heat if that windstream suddenly slams into a non-moving solid surface and becomes instantly thermalized (but of course even then that would be a very short-lived event as it would correspond with a pressure rise and the deflection of the stream behind the high-pressure zone). Additionally, nor would that be the windspeed touching the surface as, obviously, wind forms boundary layers.

Secondly, hundreds of km/s from Venus escape to Mars intercept? That doesn't at all correspond to any delta-V chart I've ever seen.

Comment: Every language has its gotchas (Score 2) 319

by Rei (#49784155) Attached to: How Much C++ Should You Know For an Entry-Level C++ Job?

And it's important for new programmers to learn them - more important than learning syntax.

  For C++ for example I'd warn about classes containing pointer member variables with implicitly-defined assignment operators / copy constructors. You have Foo a and Foo b, where Foobar has a member variable "int* bar". So the newbie does "a.bar = new int[100];" then later "b = a;" then later b goes out of scope, then they try to use a.bar and the program crashes. Seems to be a very common C++ newbie mistake. Eventually they learn to see pointers in class definitions as having big "DANGER" signs over them calling their attention, and/or rely on smart pointers.

Any others that people can think of that are common?

Oh, here's one more: iterator invalidation. A newbie who's not warned about this in advance will likely get bitten by it several times before the point gets driven into their head: "if you're using a class to manage memory for you, it's going to manage memory for you, including moving things around as needed."

A CONS is an object which cares. -- Bernie Greenberg.

Working...