After a few years, I discovered a memory leak bug in my code. Unfortunately the bug was not causing any issues to be noticed until i found out about it indirectly. If you want to know more asked a question about it here: https://stackoverflow.com/?newreg=4b839ccb32864d4ca199e32714120a10 bellow there is a function addElement from a class c_string that… Read More A question about dynamic memory allocation 2
Context Playground, This works: fn get_owned_box_working<‘a>(b: Box<&’a i32>) -> Box<&’static i32> { Box::new(&42) } but this doesn’t: fn get_owned_box_broken<‘a>(b: Box<&’a i32>) -> Box<&’static i32> { *b = &42; b } error[E0308]: mismatched types –> src/lib.rs:3:5 | 3 | b | ^ lifetime mismatch | = note: expected struct `Box<&’static i32>` found struct `Box<&’a i32>` note:… Read More How to convert lifetime of boxed reference without allocating a new box?
This is the code I wrote, total beginner #include <iostream> #include <cstring> using namespace std; class Person { public: string ID; string name; string surname; string department; string email; public: //get and set functions for ID, Name, Surname, Department, Email properties string getID() { return this->ID; }; void setID(string _ID) { this->ID = _ID; };… Read More C++ Can not manage to display the class datatype array
I am having kind of a trouble adapting a program from C# to C++. It’s very commom given a class to assign it the null value. But C++ is not accepting the equivalent form ‘nullptr’ class Point{ public: int x,y; } //… Point p = nullptr; There is some way of solving it? >Solution :… Read More Assigning general classes as null in C++
i’m trying a new assignment i’ve got: i need to copy the Environment variables from the shell into an array, then lowercase them and print them back. (i’m using Ubuntu 20.04.4 LTS, gcc for compiling, and writing my code in C language). i was adviced to use malloc to create the array but decided not… Read More Valgrind message: Conditional jump or move depends on uninitialised value(s) unresolved
Say we have a C++ program with this sort of class inheritance: class A { public: virtual ~A() {/* … */} }; class B : public A { public: virtual ~B() {/* … */} }; class C : public A { public: virtual ~C() {/* … */} }; And furthermore, there are specialized memory constraints… Read More How do I correctly destruct a derived object that was constructed using placement new
I’m a new C++ programmer, so I never wrote C++ code for anything older than C++11. I was reading Scott Meyers "Effective C++, 2nd Edition" (I know it is old, but I think it still has some valid points). In the book, according to "Item 7", new can throw exceptions which should be handled. Can… Read More Can new still throw an exception?
I noticed that when others are getting this problem, it is because they are trying to cast objects. I am not trying to cast. Furthermore, I am trying to ask if an object exists in a data table using Spring Boot repository. The following issue is occurring: What is the issue exactly? The model: @Entity… Read More Class X cannot be cast to class Boolean (X is in unnamed module of loader 'app'; Boolean is in module java.base of loader 'bootstrap
I’m programming a server – client application with a shared utils.cpp. So the server and client use the (in utils.h) predefined methods: int listening_socket(int port); int connect_socket(const char *hostname, const int port); int accept_connection(int sockfd); int recv_msg(int sockfd, int32_t *operation_type, int64_t *argument); int send_msg(int sockfd, int32_t *operation_type, int64_t *argument); So far, so good. But since… Read More C++ Segmentation fault when changing (int32_t *) pointer within method call
I have read some hints here and there that after inserting an object into a c++ stl map, then as long as one doesn’t delete it, its location in memory never changes. But nobody ever mentioned any literature or sources to back it up, so I don’t know how reliable such hints are. Can anyone… Read More Does a C++ STL Map move a value's location around after creation?