Objective-C - 如何提高浮点数的精度 [英] Objective-C - How to increase the precision of a float number

问题描述

有人可以告诉我如何设置一个浮点数的精度到所需的长度。说我有一个号码2504.6。正如你所看到的，这里的精度只有1.我想把它设置为6.我需要这个，因为我把这个值与从
[txtInput.text floatValue]中获得的值进行比较。即使我在文本框中输入了2504.6，它也会增加5个精度，而且会是2504.600098。而当我比较这两个值时，它们看起来是不相等的。

解决方案

您可以使用 NSDecimalNumber ：

  NSDecimalNumber * number = [NSDecimalNumber numberWithFloat：2504.6f]; 
 NSDecimalNumber * input = [NSDecimalNumber decimalNumberWithString：txtInput.text]; 
 NSComparisonResult result = [number compare：input]; 
 
 if（result == NSOrderedAscending）{
 // number<输入
} else if（result == NSOrderedDescending）{
 // number>输入
} else {
 //数字==输入
} 
  

Can someone please show me the way to set the precision of a float number to desired length. Say I have a number 2504.6. As you see the precision here is only 1. I want to set it to six.I need this because I compare this value with the value obtained from [txtInput.text floatValue]. And even if I enter 2504.6 to the text box it will add 5 more precisions and will be 2504.600098. And when I compare these two values they appear to be not equal.

解决方案

You can compare the numbers using NSDecimalNumber:

NSDecimalNumber *number = [NSDecimalNumber numberWithFloat:2504.6f];
NSDecimalNumber *input = [NSDecimalNumber decimalNumberWithString:txtInput.text];
NSComparisonResult result = [number compare:input];

if (result == NSOrderedAscending) {
    // number < input
} else if (result == NSOrderedDescending) {
    // number > input
} else {
    // number == input
}

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