Advertisements I’m trying to make a Discord bot, one of its features is that it plays chess, at the start of the command, I read the JSON file, then check if it’s undefined since I’ll call a key from the object, so just in case it doesn’t exist already, I’ll create the data needed Problem… Read More Variable throws initialization error after initializing it
Advertisements I want to declare acceptable_set and use it. But an empty vector is assigned to it. So the compiler warns. How to declare a variable and do not assign it? let mut acceptable_set: Vec<String> = Vec::new(); if opt.acceptable_set.is_none() { acceptable_set = crate::builtin_words::ACCEPTABLE .to_vec() .iter_mut() .map(|x| x.to_string()) .collect(); } else { acceptable_set = get_acceptable_set(opt) }… Read More How to declare a variable but not assign it?
Advertisements How to properly initialize a struct in Rust, with good enough encapsulations? Or more naively: how to leverage object/instance methods in the initialization/constructing process of structs? For example, as the initialization block in Kotlin: private class BinaryIndexedTree(nums: IntArray) { private val nNums = nums.size private val fenwick = IntArray(nNums + 1) { 0 }… Read More How to properly initialize a struct in Rust, with good enough encapsulations?
Advertisements Create an “UnusualClass” class in which direct and copy initialization produce different effects throughout. In particular, the attempt of direct or copy initialization should produce on the screen the print "Direct initialization" or "Copy initialization" #include <iostream> class UnusualClass{ public: UnusualClass(const int &n){ std::cout<<"Copy initialization"; } UnusualClass &operator=(const int &n){ std::cout<<"Direct initialization"; } };… Read More Make difference between copy and direct initialization
Advertisements I have a request to add data that triggers a trigger that checks one condition, and only after that adds it to the purchase table. He also swears at the lines of initializations total_rasr and id_buyer invalid number, although there are the same types in the table and in the trigger. And the biggest… Read More SQL command not properly ended errror database oracle
Advertisements I’m trying to create 2D array. int main() { int stalagmite[10][6] = { { 1, 0, 0, 1, 1, 0, 1, 0, 0, 1 }, { 1, 0, 0, 1, 1, 0, 1, 0, 0, 1 }, { 1, 0, 0, 1, 0, 0, 0, 0, 0, 1 }, { 1, 1, 0, 1,… Read More warning: excess elements in array initializer
Advertisements I have an array std::array<T, N> arr for some T, N and I’d like to get an array of reference over arr‘s elements like so std::array<std::reference_wrapper<T>, N> arr_ref. But as a reference needs to be set at its initialization, I did not work out a solution. Therefore I would like to do something like… Read More Reference over array into array of reference
Advertisements class MyClass: public: MyClass(const std::string& my_str); private: std::string _myStr In the implementation: MyClass::MyClass(const std::string& my_str): _mystr(my_str) How can you assign a reference (my_str is const std::string&) to a non-reference variable (_mystr, which is std::string) ? In my mental model, a variable is a block of space in memory can be filled with stuff that… Read More Why is it ok to assign a std::string& to a std::string variable in c++?
Advertisements import ‘package:flutter/foundation.dart’; import ‘package:flutter_local_notifications/flutter_local_notifications.dart’; class NotificationManager { // ignore: prefer_typing_uninitialized_variables var flutterLocalNotificationsPlugin; NotificationManager() { flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin(); initNotifications(); } getNotificationInstance() { return flutterLocalNotificationsPlugin; } void initNotifications() { // initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project const initializationSettingsAndroid = AndroidInitializationSettings(‘@mipmap/launcher_icon’); const initializationSettingsIOS = IOSInitializationSettings(… Read More argument type 'Future Function(int, String, String, String)' can't be assigned to the parameter type 'void Function(int, String?, String?, String?)?
Advertisements I would like to know where I can find some documentation about the following behavior: class Foo { public: Foo(int argX) : Foo(argX, defaultYValue) {} Foo(int argX, int argY) : x(argX), y(argY) {}; private: const int x; const int y; const int defaultYValue = -1; } Might it be possible that y value is… Read More C++ default member initialization and constructors