Regarding the number of options, C++ has quite a few IDEs: Visual Studio, Xcode, VSCode, CLion, and probably more (Oracle probably still sells the one they had for Solaris). For command-line compilers, C++ has: Visual Studio, Xcode, g++, clang++, IBM C++ compilers for their OSs, Oracle compilers for Solaris, etc.
For Ada, is there anything other than AdaCore? Is that the same as GNATStudio?
For Ada, is there anything other than AdaCore? Is that the same as GNATStudio?
Edit* - fixed Ada capitalization