lst-0098-book.cpp
// https://godbolt.org/z/cjx49ef19
namespace my {
Complex operator"" _i(const char*); // 0+ni
Complex operator"" _j(long double); // n+0i
Puzzle operator"" _puzzle(const char*, size_t);
}
using namespace my;
Complex imag4 = 4_i; // operator"" _i(const char*)
Complex real3 = 3.331_j; // operator"" _j(long double)
Puzzle p1 = "oXo" // operator"" _puzzle(const char*, size_t)
"XoX"_puzzle;