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iosobjective-cnsstringcgfloat

Converting String to Float is not giving exact value in iOS

I wrote a sample to convert string to float in Objective-C:

NSString *sampleFloatString = @"1.3";
float sampleFloatValue = [sampleFloatString floatValue];

But when I display sampleFloatValue, it shows '1.29999995'. I know it's equal to 1.3, but why is it not exactly '1.3'? Why do we need to format it explicitly? Is there any other way of doing this conversion?

Solution

  • Its called "Floating point error". The way that computers represent decimal numbers causes them to not be 100% accurate all the time:

    http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html