Template:source/doc
From Cppreference
This is one of the templates used for syntax highlighting.
{{code| 1=code| lang=language(optional)}} - base template that is intended to highlight code inline, i.e. does not enclose the code. lang is optional and defaults to text.
{{cpp| 1=code}} - shortcut for {{code| lang="cpp"}}. Highlights c++ code.
{{source| 1=code| lang=language(optional)}} - base template that is intended to highlight large amounts of code. The code is enclosed. lang is optional and defaults to text.
{{source cpp| 1=code}} - shortcut for {{source| lang="cpp"}}. Highlights c++ code.