What code compiles in the most number of languages?
3 Languages - C, C++, and Python

#ifdef _cplusplus
    #include &lt;iostream&gt;
    #define print() int main(){cout &lt;&lt; "Hello world! -- from C++" &lt;&lt; endl;}
#elif (defined __STDC__) || (defined __STDC_VERSION__)
    #include &lt;stdio.h&gt;
    #define print() int main(){printf("Hello world! -- from C\n");}
#else
import builtins
print = lambda : builtins.print("Hello world! -- from Python")
#endif

print()


Something different is printed in each language. In C &amp; C++, lines starting with '#' are preprocessing directives, but those same lines are comments in Python.