POS | Sale system. Using JavaFX

here is an MRE (showing two attempts, with debug left in to be helpful) to try and get 2d subscripting working with AT-POS across a DataFrame that has columns of Series...

I was testing this code (https://godbolt.org/z/fe6hhbeqW)...

Discussion about this was started under this answer for quite simple question.

This simple code has unexpected overload resolution of constructor for std::basic_string:

Here is a gradient color legend I created using rasterImage:

I have a graph where each node has a spatial position given by (x,y), and the edges between the nodes are only connected if the euclidean distance between each node is sqrt(2) or less. Here's my example:

I don't understand how it works. I don't know if I understood the purpose of this function wrong. I tried to search what posx=event.pos[0] means but all I found was that if you want to take x, write the code of posx,posy=pygame.mouse.get_pos() and then take posx. But I still can't understand the method he followed in the example I saw.

My goal is to create this plot in ggplot2:

After a lot of fiddling around, I managed to create it for this one dataset, as per the screenshot above, with the following rather fragile code (note the width=63, boundary=410, which took lots of trial and error):

There is a char *strchr( const char *str, int ch ) function defined in .

It has no boundary, after which it stops the search.

Is there a similar function somewhere, which you can pass a boundary to?

Edit:

I have a char* pos and a length of a substring and I want to find a specific ASCII character in it, but I don't want it to search up to the very null-terminator, because I don't care for the second part of the character sequence.

In my application a method runs quickly once started but begins to continuously degrade in performance upon nearing completion, this seems to be even irrelevant of the amount of work (the number of iterations of a function each thread has to perform). Once it reaches near the end it slows to an incredibly slow pace compared to earlier (worth noting this is not just a result of fewer threads remaining incomplete, it seems even each thread slows down).

I cannot figure out why this occurs, so I'm asking. What am I doing wrong?

A slideshow of the problem

Worth noting that CPU temperature remains low throughout.

This stage varies with however much work is set, more work produces a better appearance with all threads constantly near 100%. Still, at this moment this appears good.

Here we see the continued performance of earlier,

Here we see it start to degrade. I do not know why this occurs.

After some period of chaos most of the threads have finished their work and the remaining threads continue, at this point although it seems they are at 100% they in actually perform their remaining workload very slowly. I cannot understand why this occurs.

I have written a multi-threaded random_search (documentation link) function for optimization. Most of the complexity in this function comes from printing data passing data between threads, this supports giving outputs showing progress like: