#include <my_api.h>
int main() { return 0; }Edit: I suppose it is possible to get some version of a repl with C++ (Cling?), Java (Beanshell, Java 9?), C# (Mono, but not currently .Net?). But each of those seems generally a bit harder to get access to than simply calling gdb on a binary with debugging symbols enabled.
Visual Studio's a little bit heavyweight, but if you're programming C#, there's a good chance that's what you're using anyway.