<p>
Applying the built-in function <code>complex</code> to untyped
integer, rune, or floating-point constants yields
an untyped complex constant.
</p>

<pre>
const ic = complex(0, c)   // ic == 3.75i  (untyped complex constant)
const iΘ = complex(0, Θ)   // iΘ == 1i     (type complex128)
</pre>

<p>
Constant expressions are always evaluated exactly; intermediate values and the