Multiple Files are easy to follow

Instead of having everything jumbled up into the main cpp file, it's always best to separate your code throughout multiple header and source files. And also don't forget to name them appropriately! That way they're easy to find, easy to read, and just a lot cleaner.

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It's true that separating code into files based on what the code does helps in organization and neatness.

So if you have a bunch of type conversion functions written for a specific project put the in an appropriatly named header file and include them in your project.

It's also helpful if you have a piece of code that can be reused in other applications. Then you can just include the file again.