i want to learn C++ program

#cbook

i want to learn C++ program

#cppbookguide

#cbook

A wrong one, again

A wrong one, again

😳

read all files line by line, shuffle lines and then write.

Could you help me by showing me the code please....

Could you help me by showing me the code please....

try to write it

try to write it

I've tried many codes which haven't worked and I am just learning...I am not really good at it for know

Hello. I have a file that I have to encrypt and decrypt in C. What is the best and secured method to implement an algorithm for encryption and decryption. Any suggestions

?

Hello. I have a file that I have to encrypt and decrypt in C. What is the best and secured method to implement an algorithm for encryption and decryption. Any suggestions

dont use your own if you want ti secure

lol

I have a case study on file encryptions and decryptions. And I'm not aware of any methods

Hello. I have a file that I have to encrypt and decrypt in C. What is the best and secured method to implement an algorithm for encryption and decryption. Any suggestions

Caesar cipher is like a best one

I have a case study on file encryptions and decryptions. And I'm not aware of any methods

Just google it

you should look for libraries to do that

only ascii methods are given. I'm not satisfied with it

look at here: https://en.wikipedia.org/wiki/Blowfish_(cipher)

you have other methods too

you have other methods too

thanks. I'll look into it

you have more options too. You should research which one is the best for you

I've tried many codes which haven't worked and I am just learning...I am not really good at it for know

Google how to read file into a vector of strings, google how to write file from a vector of strings, google how to join two vectors, google how to shuffle a vector.

you have more options too. You should research which one is the best for you

👍🏻

https://en.wikipedia.org/wiki/Advanced_Encryption_Standard

thanks again👍🏻

I used to use OpenSSL some time ago when I was working on secure communications

hi friends, does someone knows a better way to reverse (reflect) bits order of a simple 8, 16, 32 and 64 bits long variable

i have optimised it a little bit, by changing the "for" end condition, from "m" to "d"... now it's faster for variables with smaller value...

i want to learn C++ program

https://google.github.io/styleguide/cppguide.html#Operator_Overloading

https://developer.ibm.com/articles/au-googletestingframework/

Here you have some interesting links, hopes can help

Could you help me by showing me the code please....

I could not

How to reduce time limit of execution

How to reduce time limit of execution

Well, you can write GOOD code

Any ideas how to make this better?

Any ideas how to make this better?

yes, use braces

Google how to read file into a vector of strings, google how to write file from a vector of strings, google how to join two vectors, google how to shuffle a vector.

Ok..

Beside writing good codes. Does input output types effect can be of considerable help ?

Beside writing good codes. Does input output types effect can be of considerable help ?

Can you write your thoughts in a way that everyone can understand, not only you?

Am i not speaking english ?

There are Libraries which provides fast input than standard iostream cin. I want to know how much fast it is !

There are Libraries which provides fast input than standard iostream cin. I want to know how much fast it is !

Standard input is fast enough

yes, use braces

Where? { res |= m; }

Standard input is fast enough

I solved a question on codechef. It stated standard input is not fast enough to carry as much as 10^8 inputs and provide output.

Can I capture "move only variable" with lambdas?!

Can I capture "move only variable" with lambdas?!

Yep [lambda_var = std::move(outside_var)](){} Since C++14

Can I capture "move only variable" with lambdas?!

Or you can capture it by reference

Where? { res |= m; }

Yes, and also I would add braces around if. Using braces just make it a bit more protected from errors (and also if there are no braces, the reader needs to check that there are no error). Also, you have res and r variables, should they be the same variable? And r declared inside the loop so you can't return it like that. Probably you need to write a test for it. I think it won't compile as it is now

Yes, and also I would add braces around if. Using braces just make it a bit more protected from errors (and also if there are no braces, the reader needs to check that there are no error). Also, you have res and r variables, should they be the same variable? And r declared inside the loop so you can't return it like that. Probably you need to write a test for it. I think it won't compile as it is now

sorry, r was res, i shortened to fit the snippet, but forgot the return

Yep [lambda_var = std::move(outside_var)](){} Since C++14

Thanks

Still it looks like it won't compile because r is declared inside the for

i don't know will the compiler calculate the mask m as constant, i don't don't want shift and multiply to be done in runtime

yes, i will pull it on top

i don't know will the compiler calculate the mask m as constant, i don't don't want shift and multiply to be done in runtime

I think a compiler will calculate m initial value at compile time, if you about this

before, i had if (!d) return r; inside the loop

and the loop end condition was m, not d... but i decided it will be slighlty faster, if iterations are limited, if there is no more 1 bits in the data to shift...

and the loop end condition was m, not d... but i decided it will be slighlty faster, if iterations are limited, if there is no more 1 bits in the data to shift...

in fact i am looking for more efficient "as speed" way to do this reflection, it must work from from 8 to 64 bit, so up to 4 functions could be instantiated from the template

I think a compiler will calculate m initial value at compile time, if you about this

i hope it will be evaluated properly, initialy i used 1<<((sizeof(T)<<3)-1), but i think * 8 is more readable...

and the loop end condition was m, not d... but i decided it will be slighlty faster, if iterations are limited, if there is no more 1 bits in the data to shift...

You need to profile it if you want to check if it really become faster. Or at least check what assembly will be generated for the function with optimization flags (you can use godbolt for that). Otherwise it's just a shot in the dark

if you want the fastest possible solution use a lookup table

Hey guys What is the suggestion for me that I can employ for ensuring my program not throwing any exceptions? (Consider I’m actually writing a service)

I’m actually from a java background and everyone would throw and catch checked exceptions commonly. But in c++ not mindfully catching an exception is really an issue. But if not to use Exception totally then we’ll end up creating a lot of bool functions/methods because we’ll have to have a bool to indicate the successful/failing result, which appears not elegant...

Thanks!

#include <stdio.h> void main(){ float score1,score2,score3,score4; printf("Masukkan 4 nilai float: \n"); scanf_s("%f",&score1); scanf_s("%f",&score2); scanf_s("%f",&score3); scanf_s("%f",&score4); printf("Skor dalam urutan terbalik adalah sebagaimana berikut: \n"); printf("%.2f\n",score4); printf("%.2f\n",score3); printf("%.2f\n",score2); printf("%.2f\n",score1); }

why i can't run with scanf_s?

#include <stdio.h> void main(){ float score1,score2,score3,score4; printf("Masukkan 4 nilai float: \n"); scanf_s("%f",&score1); scanf_s("%f",&score2); scanf_s("%f",&score3); scanf_s("%f",&score4); printf("Skor dalam urutan terbalik adalah sebagaimana berikut: \n"); printf("%.2f\n",score4); printf("%.2f\n",score3); printf("%.2f\n",score2); printf("%.2f\n",score1); }

First of all: What’s the error message 😅

https://stackoverflow.com/questions/21434735/difference-between-scanf-and-scanf-s

why i can't run with scanf_s?

Why to use scanf_s....when it can read values from scanf only

Write a C program that read 5 numbers and counts the number of positive numbers and negative numbers. How many ways in c to write this program?

Write a C program that read 5 numbers and counts the number of positive numbers and negative numbers. How many ways in c to write this program?

Million

Hey guys What is the suggestion for me that I can employ for ensuring my program not throwing any exceptions? (Consider I’m actually writing a service)

You still can use try-catch like in Java. But if for some reason you or your team don't want to use exceptions (e.g. that common in gamedev to avoid exceptions), you can achieve this by wrapping all the external libraries calls that can throw in try-catch, and use other error handling strategies in your code, including: - returning status codes (e.g. bool or enum with statuses) - returning "special" values (e.g. if your function returns only positive integers you can use negative values to signal about error) - using custom written assertions for logical errors, usually a macro that writes an error to log and terminates the application (alternatively breaks into debugger or rise a system popup) if its condition not satisfied, and this macro usually being excluded from production builds Here's a simple example of such assertion code https://github.com/gameraccoon/hide-and-seek/blob/develop/src/Debug/Assert.h

How to reduce time limit of execution

Just Press Ctrl-C

There are Libraries which provides fast input than standard iostream cin. I want to know how much fast it is !

Damn why are you asking philosophical questions?

I solved a question on codechef. It stated standard input is not fast enough to carry as much as 10^8 inputs and provide output.

There are many stupid sites don't believe everything you read.

There are many stupid sites don't believe everything you read.

Hmm

Hey guys What is the suggestion for me that I can employ for ensuring my program not throwing any exceptions? (Consider I’m actually writing a service)

Just don't throw anything and catch all inside, that is it

I’m actually from a java background and everyone would throw and catch checked exceptions commonly. But in c++ not mindfully catching an exception is really an issue. But if not to use Exception totally then we’ll end up creating a lot of bool functions/methods because we’ll have to have a bool to indicate the successful/failing result, which appears not elegant...

C++ is completely different in exception handling , you just don't need to catch all exceptions . You can start with a completely different and strange for a Java programmer approach: just forget about exceptions , ignore their existence

I’m actually from a java background and everyone would throw and catch checked exceptions commonly. But in c++ not mindfully catching an exception is really an issue. But if not to use Exception totally then we’ll end up creating a lot of bool functions/methods because we’ll have to have a bool to indicate the successful/failing result, which appears not elegant...

No you don't need returned codes and bool functions