sieve | various languages to demonstrate power | Blockchain library

There's many errors in your code including an empty array, use of pow (which is a floating-point function) and numerous logic errors that deviate from the wikipedia example code.

Here's a corrected, working version that follows the logic of the wikipedia version, with a loop afterwards to print out all the primes less than n:

In your second for loop, you start with:

Rust does not allow that in its model. You want AtomicBool with relaxed ordering.

This is a somewhat common edge case in most concurrency models - if you have two non-atomic writes of the same value to one location, is that well-defined? In Rust (and C++) it is not, and you need to explicitly use atomic.

On any platform you care about, the atomic bool store with relaxed ordering will have no impact.

For a reason why this matters, consider:

The lifetime issue is with true_block which is a mutable reference passed into the function. Its lifetime is only as long as the call to the function, but because you're spawning a thread, the thread could live past the end of the function (the compiler can't be sure). Since it's not known how long the thread will live for, the lifetime of data passed to it must be 'static, meaning it will live until the end of the program.

To fix this, you can use .to_owned() to clone the array stored in the Arc, which will get around the lifetime issue. You would then need to copy the array date out of the Arc after joining the threads and write it back to the true_block reference. But it's also not possible to mutate an Arc, which only holds an immutable reference to the value. You need to use an Arc<_>> for arc_primes and then you can mutate shared with shared.lock().unwrap()[j] = false; or something safer

I hope I'm not out of my depth here since it's been a while since I have touched C.

You could set a boolean variable to false. Within the child loop you set it to true. Add an if statement within the parent loop to check if that variable is true and break the parent loop if it is.

Quick pseudo-code:

Generally speaking, the problem is in EF Core, since AutoMapper ProjectTo just produces a Select, which you could do manually and still experience the same issue.

The problem is with nullable references. And by default AutoMapper assumes any reference type property allows null, hence the generated projection is something like this (note the conditional operator and null check):

The reason there is a difference is that you do much more iterations in your simple solution. If you change the loop from:

Your code had many compilation errors.

Oracle has a helpful tutorial, Creating a GUI With JFC/Swing. Skip the Netbeans section. Review all the other sections.

I reworked your two JPanels. When creating a Swing application, you first create the GUI. After the GUI is created, you fill in the values to be displayed.

I created the following GUI. Here's the input JPanel.

Here's the Sieve JPanel.

I used Swing layout managers to create the two JPanels. Using null layouts and absolute positioning leads to many problems.

I created the sieve JPanel, then populated it with values. You can see how I did it in the source code.

Here's the complete runnable code. I made the classes inner classes.