英文:
How to increase a float to the next multiple of 0.5
问题
我想将我的 float 值增加到它之后的第一个0.5的倍数。
例如，如果我有：float x = 3.397; 我希望它变为：x = 3.5;。或者，如果我有：float x = 7.895; 它应该变为 x = 8.0;。
英文:
I would like to increase my float value to the first multiple of 0.5 after it.
For example, if I have: float x = 3.397; I would like it to become: x = 3.5;. Or, if I have: float x = 7.895; it should become x = 8.0;.
答案1
得分: 1
简单明了，但在每个细节中都隐藏着错误。
float nextHalf(float x) {
// 已更正为：long n = Math.round(x * 2.0) + 1;
return (float) (Math.ceil(x * 2.0) / 2);
}
经过 @chux-ReinstateMonica 的更正。
由于舍入方法round/floor/ceil会以整数单位为目标进行舍入，对于0.5，必须先将数字乘以2，然后再除以2。
当然，由于浮点数中的指数在一些较大的数字中，连续数字之间的差异不再低于1.0，因此在这种情况下：
nextHalf(x) == nextHalf(x + 1.0)
英文:
Quite simple, but in every detail errors are hidden.
float nextHalf(float x) {
// CORRECTED THIS: long n = Math.round(x * 2.0) + 1;
return (float) (Math.ceil(x * 2.0) / 2);
}
With corrections due to @chux-ReinstateMonica.
As rounding methods round/floor/ceil target integer units of 1, for 0.5 one must first scale the numbers by a factor 2 and afterwards divide by 2.
Of course because of the incorporated exponent in a floating point number at some large numbers the difference between successive numbers is no longer below 1.0 so then
nextHalf(x) == nextHalf(x + 1.0)
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论