iOS - remove trailing zeros from float WITHOUT converting to String?
floating-point-precision, formatting, ios, xctest
Solution
The actual problem is that floating point math is not exact - some numbers cannot be precisely represented in binary, and due to tiny rounding errors and the such, you can't be certain of the result. For a (contrived) example, 1.0 + 1.0 = 1.99999.. This makes things like equality difficult.
The typical way you compare two floating point numbers is comparing within some error (typically called epsilon). The function you want is `XCTAssertEqualWithAccuracy`, which will compare two floats with a given precision
Problem
I would like to remove trailing zeros from a float. I found multiple posts, but all answers suggest converting a float to NSString and using NSFormatter. While this might be good in most cases, I am performing XCTests and I need the values in float - converting generated String back to float does not give correct results. For input: ``` arg0 = 0.0001; arg1 = 0.0011; ``` I would like a result of `0.0012`, but the addition `arg0 + arg1` gives the answer of `0.01200` which in turn generates a failing test for XCTest Case. My method for adding numbers is the simpliest possible: ``` -(float)addNumber:(float)first toNumber:(float)second { return first + second; } ``` And the test case as well: ``` - (void)testAddition3 { arg0 = 0.0001; arg1 = 0.0011; result = [vc addNumber:arg0 toNumber:arg1]; XCTAssertEqual(result, 0.0012, @"Addition incorrect!"); } ``` Any ideas on how to do this?