如何检查Objective-C中的NaN值(iphone sdk) [英] how to check for NaN value in Objective-C (iphone sdk)
问题描述
可能重复:
目标C - 浮动检查纳米
确定NSNumber是否为NaN
我对NaN值有疑问在CGFloat中,我如何检查数字是否有效?
I have a problem with NaN values in CGFloat, how can I check if the number is valid?
到目前为止唯一有效的方法是:
the only way so far that works is:
if ([[NSString stringWithFormat:@"%f", output] isEqualToString:@"nan"]) {
output = 0;
}
这根本不是一个很好的解决方案! :) ...而且我很确定我应该做的其他事情......
which is not a nice solution at all!!!! :) ... and I am pretty sure that there is something else I should do instead ...
推荐答案
有一个在math.h中定义检查数字是否为nan inf等(我认为你可以在没有导入的情况下使用它)。
There is a define for checking if a number is nan inf etc in math.h (you can use it without import I think).
isnan(myValue)
如果你按照定义你将最终得到
if you follow the define you will end up with
(x!=x)
还有一些其他有用的定义,如isinf, isnormal , isfinite ,...
there are also some other useful defines like isinf, isnormal , isfinite , ...
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