Visual Studio Error

I started a new file and navigated to the main.cpp section. Visual Studio has already displayed 28 syntax problems to me. I didn’t even touch anything. What should I do?

The errors you’re seeing are IntelliSense errors, not build errors. IntelliSense doesn’t always understand the project correctly, and can generate spurious errors. You can ignore these errors by clicking the “Compilazione + IntelliSense” dropdown and selecting the “Compilation errors” option.

And to hide those errors in your text editors :
Tools → Option → Text Editor → C/C++ → Advanced → IntelliSence → Disable Error Reporting