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2014/10/15 ¤U¤È 10:03:56
iphone Programming Glossary: arithmeticI am getting Expected identifier in Xcode http://stackoverflow.com/questions/12453000/i-am-getting-expected-identifier-in-xcode sqrtf powf pyAside 2 powf pyBside 2 Seems to be wanting to create a string but doesn't do anything except some arithmetic inside square brackets which isn't valid syntax. I think you want something like float answer sqrtf powf pyAside 2 powf..
http://stackoverflow.com/questions/1622729/double-vs-float-on-the-iphone cocoa touch floating point ieee 754 share improve this question The iPhone can do both single and double precision arithmetic in hardware. On the 1176 original iPhone and iPhone3G they operate at approximately the same speed though you can fit more.. you can fit more single precision data in the caches. On the Cortex A8 iPhone3GS iPhone4 and iPad single precision arithmetic is done on the NEON unit instead of VFP and is substantially faster. Make sure to turn off thumb mode in your compile settings..
What is the right choice between NSDecimal, NSDecimalNumber, CFNumber? http://stackoverflow.com/questions/1704504/what-is-the-right-choice-between-nsdecimal-nsdecimalnumber-cfnumber coding share improve this question If you are dealing with financial computations you really should use base 10 arithmetic to avoid the rounding errors that can occur with the standard base 2 floating point types. So it's either NSDecimal or NSDecimalNumber...
What are the advantages of armv7 over armv6 when compiling iPhone apps? http://stackoverflow.com/questions/3310907/what-are-the-advantages-of-armv7-over-armv6-when-compiling-iphone-apps One of the bigger differences is that the armv6 architecture has hardware support for double precision floating point arithmetic while armv7 only provides legacy software support for double precision floating point arithmetic. To compensate the armv7.. floating point arithmetic while armv7 only provides legacy software support for double precision floating point arithmetic. To compensate the armv7 architecture has a NEON unit that provides blindingly fast hardware support for single precision.. armv7 architecture has a NEON unit that provides blindingly fast hardware support for single precision floating point arithmetic. This is something you'll need to take into account if you're doing anything that involves floating point arithmetic whether..
Zooming MKMapView to fit annotation pins? http://stackoverflow.com/questions/4680649/zooming-mkmapview-to-fit-annotation-pins
OpenGL ES, OpenFrameworks, Cinder and IOS creative development http://stackoverflow.com/questions/5776839/opengl-es-openframeworks-cinder-and-ios-creative-development need Vectors matrices cameras colour images etc and the methods that you will need to work with them normalise arithmetic cross product etc Of course you can implement all this in OpenGL but if someone's done it before why not just leverage that..
Exception Types in iOS crash logs http://stackoverflow.com/questions/7446655/exception-types-in-ios-crash-logs memory address. The address does not exist or the alignment is invalid. SIGFPE Floating point exception Invalid arithmetic operation. Can be related to integer operations despite the name. SIGPIPE Broken pipe. SIGILL Illegal processor instruction...
Coordinates all wrong on iPhone 3G? It could be your compiler http://stackoverflow.com/questions/8391307/coordinates-all-wrong-on-iphone-3g-it-could-be-your-compiler Apple developer forum thread point to a problem in the armv6 Thumb code produced by XCode 4.2's compiler which cause arithmetic on certain data structures in particular CGPoint to return completely wrong results. Such as the x value being written into..
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