<!DOCTYPE qhelp PUBLIC

"-//Semmle//qhelp//EN"

"qhelp.dtd">

<qhelp>

<overview>

<p>

The caret symbol (<code>^</code>) is sometimes used to represent

exponentiation but in Go, as in many C-like languages, it represents the

bitwise exclusive-or operation. The expression as <code>2^32</code> thus

evaluates the number 34, not 2³², and it is likely that patterns

such as this are mistakes.

</p>

</overview>

<recommendation>

<p>

To compute 2^{<code>EXP</code>}, <code>1 &lt;&lt; EXP</code> can be

used. For constant exponents, <code>1eEXP</code> can be used to find

10^{<code>EXP</code>}. In other cases, there is <code>math.Pow</code>

in the Go standard library which provides this functionality.

</p>

</recommendation>

<example>

<p>

The example below prints 34 and not 2³² (4294967296).

</p>

<sample src="MistypedExponentiation.go" />

</example>

<references>

<li>GCC Bugzilla: <a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90885">GCC should warn about 2^16 and 2^32 and 2^64</a></li>

</references>

</qhelp>