hmm, you're right. Modifying my AC C++ code without semicolons for TEST and then submitting it as C resulted in a NZEC. I assumed that C and C++ would behave in the same way here, but they didn't. Also, I don't have any sort of return statement in my code for EXPR2, but it terminates normally; when I submitted this code to TEST, it also terminated normally (but with WA, of course.) So it appears that behaviour is undefined when a return statement is not explicitly used (too lazy to consult the standards though 
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What I found to work is #include and terminate the program with if(exit(0),0){}
