How to download and setup cpp-smallpt
Open terminal and run command
                                            git clone https://github.com/matt77hias/cpp-smallpt.git
                                        
                                        git clone is used to create a copy or clone of cpp-smallpt repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with cpp-smallpt https://github.com/matt77hias/cpp-smallpt/archive/master.zip
Or simply clone cpp-smallpt with SSH
                                            [email protected]:matt77hias/cpp-smallpt.git                                    
                                    If you have some problems with cpp-smallpt
You may open issue on cpp-smallpt support forum (system) here: https://github.com/matt77hias/cpp-smallpt/issuesSimilar to cpp-smallpt repositories
Here you may see cpp-smallpt alternatives and analogs
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