fstream | Advanced FS Streaming for Node | File Utils library
kandi X-RAY | fstream Summary
kandi X-RAY | fstream Summary
Like FS streams, but with stat on them, and supporting directories and symbolic links, as well as normal files. Also, you can use this to set the stats on a file, even if you don't change its contents, or to create a symlink, etc. So, for example, you can "write" a directory, and it'll call mkdir. You can specify a uid and gid, and it'll call chown. You can specify a mtime and atime, and it'll call utimes. You can call it a symlink and provide a linkpath and it'll call symlink. Note that it won't automatically resolve symbolic links. So, if you call fstream.Reader('/some/symlink') then you'll get an object that stats and then ends immediately (since it has no data). To follow symbolic links, do this: fstream.Reader({path:'/some/symlink', follow: true }). There are various checks to make sure that the bytes emitted are the same as the intended size, if the size is set.
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QUESTION
my code is working fine. Its showing the right results in the file but after executing the code,an error message pops up saying "character_array.exe has stopped working". Can anyone tell why that error appears??
...ANSWER
Answered 2022-Apr-11 at 18:07I am assuming that your issue is an infinite loop, if your IDE supports breakpoints, I would recommend adding one to your while loop and seeing if it runs forever.
QUESTION
I'm building a code that must search for a line of text in a string variable that contains many lines of text (example the text variable has lines formed like this MILAN;F205).
Once the user has entered the city he wants to search for, the program must search the database for the city entered by the user (in this case Milan) and extract only that line so in this case it extracts MILAN;F205 and puts it in the variable result.
ANSWER
Answered 2022-Apr-10 at 21:52You could:
- read your input stream into a vector of lines, and
- walk that vector of lines checking if it starts with a given city name;
- copying those lines that do match to an output vector (or just printing them out, or whatever).
The example below:
- uses a
std::istringstreaminstead of astd::fstreamas input, and - takes the walk of the input lines and the creation of the output vector to a
filter_by_cityfunction.
QUESTION
I am trying to learn programming and in our school we have exercises which are automatically checked by a bot. The time limit is 1 second and the memory limit is 1024 mb. I've tried sorting the array in an ascending order and then multiplicating the 2 highest numbers but that was too slow(my sorting algorithm could be slow so if possible suggest a sorting algorithm.) This is the fastest way that I've been able to do:
...ANSWER
Answered 2022-Apr-09 at 15:29You don't need to sort the entire array - you just need the two largest positive numbers and the two smallest negative numbers. Everything in between is inconsequential.
Instead, you can go over all the input and keep track of the two largest positive numbers and two smallest negative numbers.; At the end of the iteration, multiply each pair (if found), and compare the results.
QUESTION
I am trying to sort my file contents as double in the ascending order
My input file contains for example these lines:
...ANSWER
Answered 2022-Mar-14 at 13:23The issue here, as pointed out in comments, is that std::less sorts your strings lexicographically (i.e. the same order as it would appear in a dictionary).
This is not the intended behaviour since the sort will be then performed character by character and not value by value.
To achieve the correct behaviour, you need to make a custom comparator that will extract the double value to perform the sorting based on it.
For example (using a lambda):
QUESTION
I need to listen to User Data Stream, whenever there's an Order Event - order execution, cancelation, and so on - I'd like to be able to listen to those events and create notifications.
So I got my "listenKey" and I'm not sure if it was done the right way but I executed this code and it gave me something like listenKey.
Code to get listenKey:
...ANSWER
Answered 2022-Mar-09 at 09:38I just figured this out myself and I was able to get mine to work so I'll try my best to guide you. I believe you're just missing this line of code after you create your WebSocket object:
QUESTION
I'm tackling a exercise which is supposed to exactly benchmark the time complexity of such code.
The data I'm handling is made up of pairs of strings like this hbFvMF,PZLmRb, each string is present two times in the dataset, once on position 1 and once on position 2 . so the first string would point to zvEcqe,hbFvMF for example and the list goes on....
I've been able to produce code which doesn't have much problem sorting these datasets up to 50k pairs, where it takes about 4-5 minutes. 10k gets sorted in a matter of seconds.
The problem is that my code is supposed to handle datasets of up to 5 million pairs. So I'm trying to see what more I can do. I will post my two best attempts, initial one with vectors, which I thought I could upgrade by replacing vector with unsorted_map because of the better time complexity when searching, but to my surprise, there was almost no difference between the two containers when I tested it. I'm not sure if my approach to the problem or the containers I'm choosing are causing the steep sorting times...
Attempt with vectors:
...ANSWER
Answered 2022-Feb-22 at 07:13You can use a trie data structure, here's a paper that explains an algorithm to do that: https://people.eng.unimelb.edu.au/jzobel/fulltext/acsc03sz.pdf
But you have to implement the trie from scratch because as far as I know there is no default trie implementation in c++.
QUESTION
#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std;
class MathClass {
private:
size_t current_capacity;
double* logfact;
bool inited = false;
MathClass() {
current_capacity = 0;
logfact = new double[1];
logfact[0] = 0;
}
void calculateLogFact(int n) {
if (current_capacity >= n) return;
double* newLogfact = new double[n+1];
for (int i=0; i<=current_capacity; i++) newLogfact[i] = logfact[i];
for (int i=current_capacity+1; i<=n; i++) newLogfact[i] = newLogfact[i-1] + log(double(i));
delete[] logfact;
logfact = newLogfact;
}
double factorial(int n) {
cout << "n = " << n << "\n";
calculateLogFact(n);
for (int i=0; i<=n; i++) cout << int64_t(round(exp(logfact[i]))) << " ";
cout << "\n";
return exp(logfact[n]);
}
public:
static double factorial2n(int n) {
static MathClass singleton;
return singleton.factorial(2*n);
}
};
int main(int argc, char** argv)
{
cout << MathClass::factorial2n(10) << "\n";
return 0;
}
ANSWER
Answered 2022-Feb-16 at 10:40I agree with comments: Why hide the fact that MathClass caches results from the user? I, as a potential user, see no real benefit, rather potential confusion. If I want to reuse previously cached results stored in an instance I can do that. You need not wrap the whole class in a singleton for me to enable that. Also there is no need to manually manage a dynamic array when you can use std::vector.
In short: The alternative to using a singleton is to not use a singleton.
QUESTION
I read some posts (that don't exist anymore) and came up with the following code that generates a PFX certificate. It works fine to the part of creating this self-signed certificate.
I'm trying to expand this to crate a self-signed certificate and from that one, create it's "childs". I tryed many things but none of then actually export the certificate with it's chain as result.
The current code get's to a point of exporting a PFX with a containing CA and importing it would include both certificates, but not associate then with each other.
It's kind of a long code, but the action should work on the last "Create" funcion of it.
...ANSWER
Answered 2021-Dec-26 at 12:52I would say aim for these qualities in development certificates:
- A root certificate authority file, eg
myRoot.ca - A password protected PKCS12 file (containing a private key + certificate), whose root is the above CA, eg
mySslCert p12.
- The latter can also be a wildcard certificate, eg usable for multiple subdomains under
*.mycompany.com, which is useful in terrms of simple administration.
CREATION
Personally I prefer to use OpenSSL to create certs, since this is the technology that secures the internet, and I am then sure that there is nothing technology specific about certs issued.
See my certificates repository and the makeCerts.sh file, for sone OpenSSL commands:
- Create Root CA keypair
- Create Root certificate
- Create SSL keypair
- Create SSL certificate signing request (which can be for a wildcard certificate)
- Create SSL certificate
- Create password protected PKCS12 file
If you want to use C# to create certs, then you need to follow the same 6 steps and produce the same files. Hopefully this makes your requirements clearer.
DEPLOYMENT
In real environments these days, you may end up deploying the Root CA file (mycompany.ca.pem in my example) and the PKCS12 file (mycompany.ssl.p12 in my example).
This is quite common in Private PKI setups within a private network, so it can be very useful to simulate on a Developer PC. My .NET Example API uses the certs issued, though in some cases I use tools such as cert-manager to automate the issuing.
QUESTION
I need to write a large array of data to disk as fast as possible. From MATLAB I can do that with fwrite:
ANSWER
Answered 2021-Nov-29 at 18:52[This is a partial answer only, unfortunately.]
This is a Windows problem. I tried reproducing your results on macOS, and found a different, interesting behavior. I modified your code to distinguish between the C fwrite and the C++ std::fwrite, and I added code to write using the lower-level Posix write.
This is the C++ code:
QUESTION
I made some tests with std::ifstream on MSVC, when reading binary files. I have big performance differences between char and unsigned char data types.
Results when reading a 512 MB binary file:
...ANSWER
Answered 2021-Aug-09 at 23:12I've tracked this down to C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\include\fstream file, line 549:
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