@programminginc - страница 1913

Anonymous

https://pastebin.com/uSZNZTa6

Anonymous

so i have three documents, a makefile, a main.c file, and a csv file with some data. if you look at the make file its suppose to reroute the input for scanf from the keyboard to the csv file, so the data input is coming from the csv file, and the output is suppose to be a json file, the thing is the output file does not output properly

Anonymous

its seems to not be getting the data from the csv file

Anonymous

the csv file has 4 elements of data per student, an id number, first, lastname, and age

Anonymous

separated by ‘:’

Anonymous

same as i did in the scanf in the main.c file

Anonymous

the make file , just makes an object file, compiles the object file, executes , and opens the json file that is suppose to the output

Anonymous

the issue seems to be the input

Amir

I have read the rules and I'll follow

Anonymous

nvm guys

Anonymous

figured it out scanf("%i:%19[^:]:%19[^:]:%i",&id,firstName,lastName,&age);

Anonymous

i had to change the format specifier for the string

Anonymous

[^:] basically mean keep feeding me characters until i see : then end

Pete

Quick sort algorithms using partition:

Pete

I have to get the first element, a randomized element, and the median. I’ve done 2 but I wanna run through the logic of the median one.

Pete

So I have 3 numbers, first element in array, last, and middle. Can I just compare those numbers, get the mid and use that as my median?

Anonymous

Pete when did you start algorithms

Anonymous

how long after you starting learning c/c++

Pete

Maybe 1 1/2 years

Augmented

; can be used on the same row as many times as you wish

yes, i know, but some code beautifiers split these ";" on separate rows, on contrary they join multiple rows if ending with "," in a single row, until it ends as usual with ";"

Artöm

hi again friends, another silly question from me: if "," is used instead of ";" to separate operations (not when defining variables), is the execution order preserved e.g. crc >>= 4, crc ^= Table[idx], crc += 1234; Will this execute as ";" was used to separate the three operations? I like to use "," to keep the expression on single row after code refactoring and "beautification"... it looks more atomic, when there are few operations to the same variable, instead of writing as single expression like: crc = ((crc>>4)^table[idx]) + 1234; What you think about that?

prefer ;, since , makes lines long and nasty

Augmented

prefer ;, since , makes lines long and nasty

yes, but sometimes, if you expressions are short, or related isn't it better ? void yellow() { r = 100, g = 100, b = 0; }

Artöm

yes, but sometimes, if you expressions are short, or related isn't it better ? void yellow() { r = 100, g = 100, b = 0; }

No

Artöm

If this rgb stuff is repetitive, I'd make another function to set things up

Artöm

And I always break after {

Artöm

Just preference

Artöm

And I always break after {

Even in one-line if, yep

Augmented

No

i just gave short simple example... with "," you can list few operations without { }, after while, for, etc

Artöm

I'd like to see it splitted to 5 lines

Artöm

i just gave short simple example... with "," you can list few operations without { }, after while, for, etc

I dont' need to, it bothers readability of my code

Augmented

I dont' need to, it bothers readability of my code

is this ugly? (not readable)

Artöm

I instantly think why while was used and not for

Augmented

Artöm

Yhis usage is a sign that code block is not that simple and you need {} at least

Augmented

I instantly think why while was used and not for

i omit the iterator variable

Artöm

This hurts readability without positive perfomance income

Artöm

Assembly is same I suppose

Augmented

okay

Augmented

is it better now?

バレンタインがいない柴（食用不可）

I suggest you to watch CppCons as well, it will boost your knowledge

:) thank you very much @unterumarmung !

Augmented

This hurts readability without positive perfomance income

is it more readable with "for" constuction like that

Augmented

or it is better this way

Augmented

Artöm

for (size_t i = 0; i < size * sizeof(Type); ++i) { update(pBytes[i]); }

Artöm

Nice and clear

Augmented

for (size_t i = 0; i < size * sizeof(Type); ++i) { update(pBytes[i]); }

i affraid that compiler might recalculate size*sizeof(Type) multiple times, when evaluating for condition

Artöm

No sane one would

Artöm

If it bothers you, do size_t iters_amt = i < size * sizeof(Type);

Augmented

No sane one would

some processors have indexing registers, some have pre and post increment and decrement addressation

Artöm

Same I guess. Both are self explanatory and understandable

Augmented

Same I guess. Both are self explanatory and understandable

I mean like performance, incrementing with 1 should be faster, than adding base with index

Augmented

I mean like performance, incrementing with 1 should be faster, than adding base with index

if I use indexing [], then typecast can be inlined, instead of having const pointer

Augmented

however, this approach with [i] compiles 30 bytes longer, than incrementing the dereferenced pointer as parameter for update()

Artöm

I mean like performance, incrementing with 1 should be faster, than adding base with index

https://godbolt.org/z/01XuXu same even on -O1

Artöm

This code is just wrong

Artöm

Cast needs to be performed before indexing

Artöm

Also same for a structure https://godbolt.org/z/XAY9g7

Augmented

Cast needs to be performed before indexing

yes, my bad, indeed it was wrong...

Augmented

yes, my bad, indeed it was wrong...

your suggestion is quite nice, thank you... it's strange that having ++bytes in "for" is 8 bytes longer, compared to update(*bytes++);

Augmented

your suggestion is quite nice, thank you... it's strange that having ++bytes in "for" is 8 bytes longer, compared to update(*bytes++);

it's also resolves my fear that some stupid compiler can multiply multiple times while evaluating the "for" condition, counting down to 0 is quite smart too, thank you again

Augmented

This code is just wrong

Sorry, I replyed to myself few times, i mean THANK YOU, here is my full unit, https://godbolt.org/z/DCfb2F any other suggestions, which can lead to better readability and portability aswell?

Abdullateef

Ok

Ilya

yes, i know, but some code beautifiers split these ";" on separate rows, on contrary they join multiple rows if ending with "," in a single row, until it ends as usual with ";"

Don't use code formatters

Ilya

yes, i know, but some code beautifiers split these ";" on separate rows, on contrary they join multiple rows if ending with "," in a single row, until it ends as usual with ";"

In general I would not recommend using comma instead of semicolon. They have slightly different semantics.

Augmented

is this better, or not?

Augmented

hello everybody, is ternary operator, more readable, than if/else ?

Francisco

This one is definetely clearer

Augmented

This one is definetely clearer

okay, but it's so simpler with the ternary operator, and the comment above clarifies everything? is it allowed to use such constructions, when its not something complicated, and the comment above is explainatory... or we should keep things selfexplainatory but longer...

Francisco

is this better, or not?

Here, we might think _instance is a bool, therefore hiding important information. The comparison with NULL makes it a hundred times clearer (although nullptr should be used). Also, complex constructs via ternary operator are probably not what you want

Francisco

I would reject the second snippet and enforce the use of nullptr in the first one

Augmented

I would reject the second snippet and enforce the use of nullptr in the first one

okay, thank you so much, NULL is a macro for nullptr, i made for a specific platform port, i will switch to the built-in nullptr

Francisco

okay, thank you so much, NULL is a macro for nullptr, i made for a specific platform port, i will switch to the built-in nullptr

nullptr is not built in, but rather a variable of type nullptr_t, that's way safier than NULL

Augmented

Francisco

An if is still way more readable. And you really don't gain anything with the ternary

Augmented

An if is still way more readable. And you really don't gain anything with the ternary

yes, i understand, but somehow i am tempted by the single line expression 🙂

Francisco

yes, i understand, but somehow i am tempted by the single line expression 🙂

A one-liner is not always that readable. We're not in Python

Augmented

A one-liner is not always that readable. We're not in Python

I came from assembly, Python I still avoid like hell... I like C, now i am mostly going for a full C++, but still learning and asking people silly questions... Thanks to all of you guys for the help