The tool turns every text line into a paragraph element instead of turning text with spaces between them as paragraph elements.
How Should it Work?
THIS IS A TEST THIS IS A TEST
This is a test
THIS IS A TEST THIS IS A TEST
Should be parsed to this:
<p>THIS IS A TEST THIS IS A TEST This is a test</p>
<p>THIS IS A TEST THIS IS A TEST</p>
It's dangerous to work with filenames and paths as though they are strings, and make assumptions about how they will be constructed. Especially as you move between operating systems and filesystems, the standards change.
The README is mostly aimed at developers who want to build the code. It should also include details for users you want to run the code. You should discuss how the program works (e.g., flags, args to pass, and their meaning), show examples, and give a sense of the kind of input/output to expect.
A missing feature is to extract and use the title of the document, as defined by a line of text with 2 empty lines after it at the start. This should be used to populate the title and an h1 element.
Working with C++ is a great way to target multiple operating systems and platforms. Doing so requires you to have a build system that works across various systems. Currently there is no build system, and you give a manual command to compile the code.
The README does not contain information on the tools features or examples. If there was more information on what can be done with tool and some examples of how to use these features, it would make the tool easier to use.