Xcode Download and Install for your computer - either Windows PC 10, 8 or 7 and macOS 10 X, 32/64-bit processor, we have you covered.
This version includes the SDKs for iOS 14, iPadOS 14, macOS Catalina, tvOS 14, and watchOS 7. Download from the Mac App Store.
You may have to sign up for a free Apple Developer Account in order to download Xcode 10 from the developer link that BDAqua provided — unless Apple has relaxed its access privileges for these tools.
Xcode 11.1 Download
Install Xcode Mac
Alternatively, If all you want is a a compilation environment for Objective-C, C++, and Swift v4.n, the Command Line Tools (macOS 10.13) for Xcode will provide that at 7GB less storage. You would then need a competent programmer's editor, and you can still build hand-coded cocoa applications. This is my preference.