Where Can I Collect Malware Source Codes?

Could anyone know the way to gather malware source code like the following link.

I need the original source code such as cpp file.

On the purpose of my research, I have to collect as much and up-to-date malware “original” source code as possible.

Please tell me any idea.

The Github repository awesome-malware-analysis has a section called ‘Malware Corpora’ where they list repositories similar to the one you provided. Additionally, there is another section called ‘Honeypots’ linking to tools intended for capturing malware samples.