CppDroid - C/C++ IDE - Apps on Google Play is a working C Compiler in Android. The installation takes some time. The initial download is around 46 MB. But then it downloads about 100 packages, which majorly consist of tutorial programs.

Points to note:

Please use int main and consequently end with return 0;

A recommended Online C Compiler is Ideone.com

Here, select C as the language to code in, and you are all set.