|
It's the little things like this that's practically forcing me to learn to Zig. I mean... C should be getting some of this stuff so it stops falling so far behind. I mean, why leave systems languages in the dust?
Such as being able to use underscores to increase readability in long numbers. I mean C# has had it for a while now. What gives?
const jenny: u32 = 867_5309 // don't lose my number
Jeremy Falcon
|
|
|
|
|
Are you suggesting that underscore is significantly better than single quote[^]? Number formatting has been available since C++14.
Mircea
|
|
|
|
|
Does that apply to C as well? If so, I never knew that. Let me try it real quick...
Nope, just tried real quick with an online compiler. It's still a no-go for C. Which is sad IMO, would love to see C see these (say that 5 times real quick).
Jeremy Falcon
|
|
|
|
|
Never heard of that in C#. Seems pointless, so I guess they probably added it.
|
|
|
|
|
Well in C, took us over a decade to a get a bool. So ya know, it's easy to impress me.
Back in the day if I had a large number I'd just do something like this in a comment beside it:
const int bruh = 123456789;
So, it's not like a huge lifesaver since the comment would serve the same purpose. Just wanna those neat little things.
Jeremy Falcon
|
|
|
|
|
|
We special now.
Jeremy Falcon
|
|
|
|
|
Dagnabit, I step away for twenty years and everything changes.
Having said that... I expect that HP hasn't advanced DEC/Compaq/HP C for OpenVMS.
|
|
|
|
|
Wait, what?
Why the heck would you add commas for large numbers? It's a number. First, if you are entering large numbers like this in your code in the middle of processing, you need to have your code reviewed. This falls under a magic number. A very long time ago, and I'm being sarcastic, we'd do this:
#define _A_VERY_LARGE_NUMBER 12345678901234
Better yet, we'd so something like:
// Folks, we use metric in this code. If you introduce english units, I will haunt you from the grave.
#define SPEED_OF_LIGHT_METERS_PER_SEC 299792458
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
|
|
|
|
|
So, you're saying I should avoid something like this?
#include <stdio.h>
#include <math.h>
#define ONE 123
#define TWO 456
unsigned concatenate(unsigned x, unsigned y) {
unsigned pow = 10;
while(y >= pow) pow *= 10;
return x * pow + y;
}
int main()
{
printf("Bro %d", (int)concatenate((unsigned)ONE, (unsigned)TWO));
return 0;
}
Jeremy Falcon
|
|
|
|
|
lol. yup. Don't be stupid.
Decades ago, I ran a development group. I had a rule - need a book, buy it and submit an expense form. I had people with 10+ years of development experience freeze up. What, I don't need approval first? Nope, apply common sense and the intelligence I'm paying you for. My welcome intro speech was, "You shall use source control. If you have an issue with this, resign now."
Sadly, your example is code I have seen.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
|
|
|
|
|
Extracting magic numbers as named constants is usually a good idea, but orthogonal to the question of whether an underscore separator is helpful or not. It absolutely is helpful if you're dealing with number with mure than 7 or 8 digits. There's a reason we use commas (or periods in continental Europe) to break numbers into groups of 3 digits: it makes it much more obvious when a digit is missing (or erroneously present).
|
|
|
|
|
fair enough. So:
#define SPEED_OF_LIGHT_M_PER_SEC 299,792,458
I understand your point, but I abhor magic numbers in code even if I know what they mean. I hate magic functions, and don't get me started on hideously complex macros that cannot be debugged.
Hex constants are okay as well, since I can transpose the bits in my head while reading - but I can see the benefit of breaking up long hex strings when you are masking say a 64 bit value.
The ultimate goal is to avoid errors.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
|
|
|
|
|
charlieg wrote: The ultimate goal is to avoid errors.
Yep! And I agree with you that magic numbers run counter to that, since there's no visible, verifiable logic within them - you just have to somehow know that it's correct. When I was learning 68000 assembly in the 1990s, I'd read freely-available source code and see moves to and from arbitrary memory addresses for device I/O etc, and wonder how often people accidentally used the wrong address (or one that may only be valid if your machine has exactly 512kb RAM).
Where possible I'll try to push back on the inscrutability a bit, like defining
SECONDS_PER_DAY as
60*60*24 instead of
86400 .
|
|
|
|
|
C# binary literals:
const uint bitmask = 0b0010_0000_0000_1100_0000_0001_0000_1111; The underscores are useful, no?
Software Zen: delete this;
|
|
|
|
|
I'd use hex.
modified 19-Aug-24 11:34am.
|
|
|
|
|
The binary literals are handy for hardware register bits. This is especially true when the documentation is written by a hardware engineer who documents things by bit numbers rather than masks. Defining this sort of thing with hex is okay, but it takes more time when reading.
Software Zen: delete this;
|
|
|
|
|
VB has datetime literals, I'd find them more useful in my work.
|
|
|
|
|
C won't ever get up-to-date as C proponents don't want anything modern.
It's not like system languages get left in the dust though, Rust is having some exciting evolution.
|
|
|
|
|
Yeah, and what makes it worse is that C is use everywhere. So now there are huge committees involved, so things (even if they did happen) will take a while to get ratified and accepted.
Jeremy Falcon
|
|
|
|
|
It's not (only) that. C++ is driven by a commitee and those guys managed to create a (mostly) modern, pleasant programming language. Rust is driven by a commitee. It's less about commitees and more about specifically C, it attracts a certain kind of people and that certain kind of people keep C the way it is.
|
|
|
|
|
Ruffnik wrote: it attracts a certain kind of people and that certain kind of people keep C the way it is. Gotta agree with you there, buddy.
Jeremy Falcon
|
|
|
|
|
We'll eventually die off and leave you with it as well as the COBOL.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
|
|
|
|
|
So, curious question... even if you are trafficking in .c files, why aren't you using a C++ compiler to compile your C code?
Even in embedded environments, C++ is preferred to C. If you must strictly conform to C++ only as better C, and avoid polymorphism, exception handling and RTTI, you are still left with one very powerful tool at your disposal - templates!
Using stupid template tricks, you can easily strip your number of the thousands separator, or indeed, any delimiter such as the '-' (dash) in sweet Jenny's phone number.
It might look something like this:
#include <iostream>
#include <string>
#include <algorithm>
std::string removeThousandsSeparators(const std::string& formattedNumber)
{
std::string result = formattedNumber;
result.erase(std::remove_if(result.begin(), result.end(), {
return !std::isdigit(c);
}), result.end());
return result;
}
Here is an example of how it might be used:
int main()
{
std::string formattedInput = "1,234,567";
std::string strippedNumber = removeThousandsSeparators(formattedInput);
std::cout << "Formatted input: " << formattedInput << std::endl;
std::cout << "Stripped input: " << strippedInput << std::endl;
return 0;
}
If you dislike the idea of having to quote your value, you can also add a pre-processor macro to handle that as well:
#define STRINGIZE(x) #x
You can then use it like so:
auto strippedNumber = removeThousandsSeparators(STRINGIZE(1,234,567));
Keep in mind, all of this is done at compile time, so there is no performance penalty.
When there's a will, there's a relative.
|
|
|
|
|
Stacy Dudovitz wrote: So, curious question... even if you are trafficking in .c files, why aren't you using a C++ compiler to compile your C code? To be honest, habit. Back in the day I adopted the when in Rome mantra, as in if I'm gonna do C just use a C compiler to help make sure I don't do anything "non-C" in it.
That's the only reason. Now I've just done it so long it's just what I do.
Stacy Dudovitz wrote: Here is an example of how it might be used: Per my understanding, if I used the C++ standard libs I'd have to link to the C++ library as well, in conjunction with the C libs. So, I would incur a penalty when it came to runtime requirements if I did that.
Stacy Dudovitz wrote: Keep in mind, all of this is done at compile time, so there is no performance penalty. The out of the box thinking is awesome. Great post.
Stacy Dudovitz wrote: When there's a will, there's a relative.
Jeremy Falcon
|
|
|
|