Is there an interpreter for C?

picoc - A very small C interpreter

PicoC is a very small C interpreter for scripting. It was originally written as the script language for a UAV's on-board flight system. It's also very suitable for other robotic, embedded and non-embedded applications.

There are many - if you narrow down the scope of your question we might be able to suggest some specific to your needs.

A notable interpreter is "Ch: A C/C++ Interpreter for Script Computing" detailed in Dr. Dobbs:

Ch is a complete C interpreter that supports all language features and standard libraries of the ISO C90 Standard, but extends C with many high-level features such as string type and computational arrays as first-class objects.

Ch standard is freeware but not open source. Only Ch professional has the plotting capabilities and other features one might want.

I've never looked at this before, but having a c interpreter on hand sounds very useful, and something I will likely add to my toolset. Thanks for the question!

---

Edit:

Just found out that one of my favorite compilers, TCC, will execute C scripts:

It also handles C script files (just add the shebang line "#!/usr/local/bin/tcc -run" to the first line of your C source code file on Linux to have it executed directly.

TCC can read C source code from standard input when '-' is used in place of 'infile'. Example:

echo 'main(){puts("hello");}' | tcc -run -

the ROOT project provides a very functional C and C++ interpreter called Cint. I'm quite fond of it. It takes a little getting used to interpretively, though.

TCC is a very good choice as well, but i'm not able to vouch for its REPL

Probably. There are several for c++. See Have you used any of the C++ interpreters (not compilers)? for examples. Certainly cint will eat nearly any c code with good results, and tcc is so fast that you can use it like a interpreter.