Swift: Double conversion inconsistency. How to correctly compare Doubles?

Question

I have a very simple function to convert temperature from ˚C TO ˚K.

func convertKelvinToCelsius(temp:Double) ->Double {
        return temp - 273.15
}
         


        

Answer 1

This is expected behavior for floating point values. They cannot be 100% accurately represented.

You can use the XCTAssertEqualWithAccuracy function to assert floating point values are within a given range of each other.

The reason println prints the same value for all is because it internally rounds them to two decimals (I assume).