Converting String to Float is not giving exact value in iOS

Question

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?

Answer 1

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

Answer 2

Try this

float sampleFloatValue = (float) sampleFloatString;

Hope it helps.

Answer 3

if you just wants to show these value somewhere than u can do these and it shows 1.3 exact..

NSString *sampleFloatString = @"1.3";
float sampleFloatValue = [sampleFloatString floatValue];
NSLog(@"%.1f",sampleFloatValue);