# C++ question

**URL:** <https://forum.kirupa.com/t/c-question/257082>\
**Category:** Uncategorized\
**Created:** [April 10, 2008, 2:05am UTC](https://forum.kirupa.com/t/c-question/257082 "2008-04-10T02:05:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![wo1olf](https://avatars.discourse-cdn.com/v4/letter/w/278dde/32.png) [@wo1olf](https://forum.kirupa.com/u/wo1olf)\
**Post date:** [April 10, 2008, 2:05am UTC](https://forum.kirupa.com/t/c-question/257082/1 "2008-04-10T02:05:44Z")

</div>

in this code

```auto

unsigned int maxsize = 1024U*1024U*1024U*2U;
int size = 1024;
(...)
for(size=128;size<maxsize/4;size+=(size/4+7)&~7) 
{
instructions here...;
}

```

my questions are:  
what does the U after 1024 stand for?  
and what does the operator &~ do in the loop?  
thnks