/in/ex2.c: In function 'main':
/in/ex2.c:21:27: error: 'X' undeclared (first use in this function)
         printf("%.0f",pow(X:a, Y:b));
                           ^
/in/ex2.c:21:27: note: each undeclared identifier is reported only once for each function it appears in
/in/ex2.c:21:28: error: expected ')' before ':' token
         printf("%.0f",pow(X:a, Y:b));
                            ^
/in/ex2.c:21:23: error: too few arguments to function 'pow'
         printf("%.0f",pow(X:a, Y:b));
                       ^~~
In file included from /usr/include/features.h:424:0,
                 from /usr/include/x86_64-linux-gnu/bits/libc-header-start.h:33,
                 from /usr/include/stdio.h:27,
                 from /in/ex2.c:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:140:1: note: declared here
 __MATHCALL_VEC (pow,, (_Mdouble_ __x, _Mdouble_ __y));
 ^