how to compare long long and unsigned long?

Where I Can Learn Flow Charts

https://en.m.wikipedia.org/wiki/Flowchart but ig better use pseudocode or python hehe

depends. struct lol { int i = 0; }; lol fn() { return {}; } int main() { // auto var = { 5 }; // doesn't work auto var = lol{5}; // works auto var = fn(); // works }

What’s the curly braces mean again in case of lol{5}?

What’s the curly braces mean again in case of lol{5}?

I'm working on a project that I need to first read data from a file, then make some change to it, and then save it to another file (all in binary mode). For reading, my first try was to open the file with ifstream and read directly from the file with read(), but because I need to read small bytes from the file back to back, I think it's not a good idea to keep reading data directly from the file itself. I mean, currently I'm doing it this way for reading the file into a structure and normal variables: namespace DBinary { #pragma pack(push, 1) struct Structure { int32_t iData1; int16_t iData2; int16_t iData3; int16_t iData4a; int16_t iData4b; int32_t iData4c; }; #pragma pack(pop) } int main() { std::ifstream input(path, std::ios::binary); //for reading structure DBinary::Structure tstruc{}; file.read((char*)&tstruc, sizeof(DBinary::Structure)); //read single value uint16_t anint = 0; core_file.read((char*)&anint, sizeof(anint)); } It's OK, but I think I can do it better, because the file isn't that big. Maybe I can read it fully into memory and then work on it? But I'm not sure what is the best way to do that, and how to do that, because I don't have much experience in C++ and I'm new to it. I also want to be able to freely edit and change the data that I read from files, so its important for me to also support that.

the std::ifstream object has its own buffer. you don't need to worry about reading small amounts of data. the rdbuf() member returns a pointer to the underlying buffer, you can change the buffer size through that if you want.

is there any better optimised way for writing the function to add a specific element at a specific position in a linked list class node{ public: int data; //Date in the node node* next; //(node* denotes a pointer pointing to a node data type) Address of the next node node(int val){ data = val; next = NULL; } }; void insertatposition(node* head, int pos, int val){ node* p=new node(val); node* temp1=head; node* temp2=head; for(int i=1;i<pos;i++){ temp1=temp1->next; } for(int i=2;i<pos;i++){ temp2=temp2->next; } p->next=temp1; temp2->next=p; }

Hi, when I pass an int array with size of 10 elements to a function, and then show the sizeof this array the program print 8 byte but when I show it in main function without pass it print 40 byte why is this the case and how to handle it

Ok.. I get it. What I want to do is make for loop inside that function I try to use sizeof to know how many elements I have, so maybe I should to pass the size with the array to the function

yes, exactly. you need to pass the size too, or in some cases you will read until some charater is found (C strings use this a lot (the null byte is the end))

Hi, i am new in c program language can i get someone to teach me

what I actually after is what is the best way to create a buffer to store edited data for later to save to disk

You might have some better chance to have your first lesson from Coursera than in here I suppose :) they welcome your questions but I guess they would expect one to at least do some homework of self-learning on his own first

In cousera I'm leaning java script

You should be able to find a c++ course there

https://www.coursera.org/courses?query=c%2B%2B

same. ofstream has its own buffer. you can get a pointer to the buffer using the rdbuf() member. you can flush() the writes whenever you want, or you can set up automatic flushing with std::ios_base::unitbuf (bad idea for small writes)

thanks, but I can insert new data to the ofstream buffer? what you saying is first get a pointer to ifstream buffer with rdbuf then make some change on it and after that save it to a file with ofstream? or I get it completely wrong😅

Please......♥️ How do I delete recurring elements inside the stack

write directly with ofstream, but if you want to change the buffer size or something (for example - making it equal to (disk logical block size / your struct size)), use the rdbuf() function to do that. https://en.cppreference.com/w/cpp/io/basic_streambuf/pubsetbuf look at the example code provided here

let me ask straight, how can I create a buffer for save some data that I don't know exact size of them I mean imagine I have some strings, and I want to add each of them to a char buffer and after that add the created char buffer to another. how can I actually do that? I will be grateful if someone answer this question

maybe you can try memory mapped files, for Windows

how can this help me? there is no problem in reading and writing file I just want a good solution to be able to freely edit (and store the edited data to a buffer) and at the end write edited data to disk

Why would you need two iterations for two pointers? You can always derive for the next pointer from one pointer. So only one iteration will be fine right right?

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I feel the rules are too straight... wouldn’t ban anyone for just asking questions. That being said ...I however agree to what they try to achieve though. I’d also be pissed off if someone is just expecting an answer without thinking himself and just asking for granted. But we should be free to decide ourselves to ignore these kind of questions. We don’t really need to ban anyone here unless someone is making obvious harassment to others.

a portion of kindness)

I want to build a daily tracking app in c. Any resources you guys can point me to?

What exactly resources you want?

Where to start

for (int i = 0; i < n - 2; ++i) { int k = i + 2;👈👈 for (int j = i + 1; j < n; ++j) { while (k < n && arr[i] + arr[j] > arr[k]) ++k;

What will happen if I initialize k in the 2nd for loop

Literally nothing

So it doesn't matter if I put that line in the first loop or the second loop??

Logically it matters. Depends on what you are trying to do.

just use std::string and append it directly (if small enough like < 1MB

it is not a easy task,but you can start from here

Hi All I am building project in C for library managment. The issue is : i have structure user like : typedef struct member{ name s_name; unsigned int id; char *dept; long mobile; category cat; }member; typedef struct user{ member personal_details; char* password; }user; I dynamically allotace memeory and store the strings data from user. And i am writing this data to binary file using fwrite. example : fwrite(new_user,sizeof(user),1,ptr_of_file); But when later i access the struct members then they all give seg fault. How should i solve this issue. I have understood that issues is that we are just writing pointer and not whole data that has memory allocated. How should i stored properly ?