It is an error if any of those channels is a receive-only channel.
</p>

<h3 id="Complex_numbers">Manipulating complex numbers</h3>

<p>
Three functions assemble and disassemble complex numbers.
The built-in function <code>complex</code> constructs a complex
value from a floating-point real and imaginary part, while
<code>real</code> and <code>imag</code>