#pragma once #include"RYMath" #include "RYFrame" #include<vector> namespace RY{ class Bullet{ public: Frame finalAnimation; const Angle &InternalAngle; float vel = 1; float angle = 0; Dot<float> vector; Dot<float> position; Dot<float> target; Bullet(Angle &angle,Frame finalAnimation,float Velocity=1.f): position(Dot<float>(angle.originX,angle.originY)), vector(angle.calculateVector()), vel(Velocity), angle(angle.calculateAngle()), InternalAngle(angle), target(angle.getTarget()), finalAnimation(finalAnimation) {} void setTarget(const Dot<> &newTarget){ vector=Dots2Vector(InternalAngle.getOrigin(),newTarget); } bool update(float deltaTime = 1.f, bool updateVector = false){ Dot length = target-position; if(updateVector?true:vector>Dot(0.f,0.f)?length>Dot(0,0):length<Dot(0,0)){ if(updateVector) vector=Dots2Vector(InternalAngle.getOrigin(),InternalAngle.getTarget()); position+=(vector*vel*deltaTime); }else{ return true; } return false; } }; std::vector<Bullet> Bullets; }

error: use of deleted function 'RY::Bullet& RY::Bullet::operator=(RY::Bullet&&)' 400 | *result = std::move(*first); | This is from your error message. In C++14, there was a problem with the standard wording for erase function on vector<T> which required T to be MoveAssignable and also that the elements past the element to be erased will be move assigned. This was corrected later in C++17. So I suspected that was the issue. Here is the quote from the C++14 standard: std::vector::erase ([vector.modifiers]: Effects: ... Complexity: The destructor of T is called the number of times equal to the number of the elements erased, but the move assignment operator of T is called the number of times equal to the number of elements in the vector after the erased elements. Throws: Nothing unless an exception is thrown by the move assignment operator of T.

https://github.com/carbon-language/carbon-lang

I'm starting to understand a little bit and I'm using c++20

Hi! I need help please, so I trying create a library, but when run the compiler return an error: g++ main.cpp /usr/bin/ld: /tmp/cc0ufRYL.o: in function `main': main.cpp:(.text+0x15): undefined reference to `nDividers_PN(int)' collect2: error: ld returned 1 exit status You can find it on my github: https://github.com/Leumim2020/lib_divisorsPN/tree/main/lib_divisoresPN

The problem is that your class Ry::Bullet has a constant reference data member which causes the assignment operator to be synthesized as deleted. There will be no move assignment operator as you haven't requested it (from the code snippet you showed). If you request it explicitly, that will also be synthesized as deleted. When you call erase, the vector's implementation will try to use the move assignment operator to move the elements past the element being deleted if the move assignment operator is noexcept (since C++17. C++14 had this wrongly worded). If it can throw exceptions, the copy assignment operator would be used as a fallback. But in your case the copy assignment operator is a deleted operation. So you can't call erase on a vector holding such elements.

you have a main in your library ?

you have a main in your library ?

you have a main in your library ?

Yes, I have

library is not executable

library is not executable

Yes, I know, but how do solve this problem?

no i didnt

Hi! I need help please, so I trying create a library, but when run the compiler return an error: g++ main.cpp /usr/bin/ld: /tmp/cc0ufRYL.o: in function `main': main.cpp:(.text+0x15): undefined reference to `nDividers_PN(int)' collect2: error: ld returned 1 exit status You can find it on my github: https://github.com/Leumim2020/lib_divisorsPN/tree/main/lib_divisoresPN

You have to do g++ main.cpp main2.cpp

I must execute the file main.cpp and main2.cpp in only line?

The problem is that your class Ry::Bullet has a constant reference data member which causes the assignment operator to be synthesized as deleted. There will be no move assignment operator as you haven't requested it (from the code snippet you showed). If you request it explicitly, that will also be synthesized as deleted. When you call erase, the vector's implementation will try to use the move assignment operator to move the elements past the element being deleted if the move assignment operator is noexcept (since C++17. C++14 had this wrongly worded). If it can throw exceptions, the copy assignment operator would be used as a fallback. But in your case the copy assignment operator is a deleted operation. So you can't call erase on a vector holding such elements.

how can I make assignment operator not be deleted?

https://github.com/carbon-language/carbon-lang

This was bound to happen. With the C++ standards committee insisting on non ABI breaking changes alone, people were bound to look for something that has the appearance of a more modern language like Kotlin, Rust or Go. The GitHub page specifically says that even C++20 looks like an archaic language with concepts specifically being pointed out as being tedious.

By defining your own assignment operator. But remember that when you have a const reference member, the semantics of assignment itself changes. You can't change the const reference member. So what would it mean to assign another object with a different angle to an object when the angle cannot be changed.

C++20 concepts? Tedious? They are pretty much compile time predicates (you can actually use them as bool)

The way you need to describe them is what is tedious. Not how they are evaluated by the compiler. Look at the examples provide of how they would look like in Carbon

Hello, is there a friend we can learn programming in C language together?

I think we are all here learn C together, not python or php or anything else.

How to do waiting in C++ ?

Because I am developing a script for a game, and when using sleep, the game is pausing

Because I am developing a script for a game, and when using sleep, the game is pausing

I don't know if I understood very well but are you trying to delay only a part of the code? a function for example? maybe thread or clock help you

I don't know if I understood very well but are you trying to delay only a part of the code? a function for example? maybe thread or clock help you

I do not find it to be a less tedious syntax. I find it to be a different one, implemented very differently, and reflecting different goals. It doesn't have concepts in the same sense as C++ does, it has type erased generics with constraints comprehensions, which do something completely different and solve a similar but not identical problem

note: 'concept' only available with '-std=c++20' or '-fconcepts'

concept bool Averageable() { return std::is_default_constructible<T>::value && requires (T a, T b) { { a += b } -> T; { a / size_t{ 1 } } -> T; }; }

note: 'concept' only available with '-std=c++20' or '-fconcepts'

Hello guys! I want to know how to store a variable from int main() then use it for another function.

how can i see what compiler replace with auto in compile time i want to switch a code from cpp 20 to cpp 17 wierdly :) gcc would be grate or even compiler explorer option

Do you use an IDE? That should display the types inferred If not you can do something like this: template<typename T> struct InferredType; auto x = <something>; InferredType<decltype(x)> iType; The line above would give you a compiler error saying InferredType could not be defined (because it is an incomplete type) with the inferred type of x.

#include<iostream> #include<fstream> using namespace std; int main(){     std::ifstream inputFile("test.txt");     if(inputFile.good())         std::cout << inputFile.rdbuf()<<endl;     return 0; } This program outputs “Name: Beethoven Song: Moonlight Sonata” But my test .txt is clearly written as “Hello world “ How it comes to be Beethoven?

Hey I want to start learning C++ am so new please what materials do I even need to start

#include<stdio.h> int main() { int a[6] = {11,23,44,21,32,89}; int i,j; for(i = 0 ; i < 3 ; i++) { for(j = i+1 ; j < 3 ; j++) { if(a[i] > a[j]) { int t = a[i]; a[i] = a[j]; a[j] = t; } } } for(i = 3 ; i < 6 ; i++) { for(j = i+1 ; i < 6 ; j++) { if(a[i] < a[j]) { int t = a[i]; a[i] = a[j]; a[j] = t; } } } for(i = 0 ; i < 6 ; i++) printf("%d ",a[i]); return 0; }

Can someone explain usage of || please ? #include <stdio.h> int main() { // Write C code here int i,a=1,b=2,c=3; i= ++a |,| ++b |,| ++ c ; printf("%d %d %d %d",i,a,b,c); return 0; } *I used , between two of | , because telegram doesn't accept double |