Some user-made C functions and their D equivalents

[Dennis]

On Wednesday, 27 July 2022 at 18:19:34 UTC, pascal111 wrote:
> The library link:
> https://github.com/pascal111-fra/turbo-c-programs/blob/main/COLLECT2.H

It would help if the functions had a comment explaining what 
they're supposed to do, but it looks like most of them are string 
functions. In D, you can concatenate strings with the `~` 
operator, and utility functions like `strip` and `replace` are in 
the `std.string` module:

https://dlang.org/phobos/std_string.html

I also think you defined the equivalent of these functions:
```D
import std.algorithm: swap;
import std.math: sgn, trunc;
```