在Objective-C中转换为绝对值 [英] Convert to absolute value in Objective-C

问题描述

如何在Objective-C中将负数转换为绝对值?

How do I convert a negative number to an absolute value in Objective-C?

即

-10

成为

10?

推荐答案

根据变量的类型，abs(int)，labs(long)，llabs(long long)，imaxabs(intmax_t)，fabsf(float)，fabs(double)之一或fabsl(long double).

Depending on the type of your variable, one of abs(int), labs(long), llabs(long long), imaxabs(intmax_t), fabsf(float), fabs(double), or fabsl(long double).

这些函数都是C标准库的一部分，因此在Objective-C和普通C中都存在(并且通常在C ++程序中也可用).

Those functions are all part of the C standard library, and so are present both in Objective-C and plain C (and are generally available in C++ programs too.)

(las，没有habs(short)功能.或者scabs(signed char)就这样...)

(Alas, there is no habs(short) function. Or scabs(signed char) for that matter...)

Apple和GNU的Objective-C标头还包含一个与类型无关的ABS()宏.我不建议使用ABS()，但是不能保证它是副作用安全的.例如，ABS(a++)将具有未定义的结果.

Apple's and GNU's Objective-C headers also include an ABS() macro which is type-agnostic. I don't recommend using ABS() however as it is not guaranteed to be side-effect-safe. For instance, ABS(a++) will have an undefined result.

如果使用的是C ++或Objective-C ++，则可以引入<cmath>标头并使用std::abs()，它是所有标准整数和浮点类型的模板.

If you're using C++ or Objective-C++, you can bring in the <cmath> header and use std::abs(), which is templated for all the standard integer and floating-point types.

这篇关于在Objective-C中转换为绝对值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！