Question

I am trying to add a positive/negative button onto a numerical input in a UItextfield, but I cannot get it to function properly. What I want it to do is just add or remove a negative sign from the front of the numerical input. I am able to do that, however I cannot find a method to maintain the original number of decimal places. This is what I have tried:

- (IBAction) negsign
{
    float input = [userinput.text floatValue];
    float result = ((input * (-1)));
    negstring = [NSString stringWithFormat:
                          @"%f", result];
    userinput.text = negstring;
}

With this I get just a string of zeros after, like -23.0000000. I’ve tried limiting the decimal places by changing to @”%.2f” but I dont want extra zeros for whole integers, or rounding more than 2 decimals places. I just want it to take something like 34.658939 or 23 and make it -34.658939 or -23. Does anyone have a method to do this?

Answer 1

What would work best in your case is the following code:

float input = [userinput.text floatValue];
float result = ((input * (-1)));
NSNumber *resultNum = [NSNumber numberWithFloat:result];
NSString *resultString = [resultObj stringValue];
userinput.text = resultString;

If you’re trying to make the number negative instead of reversing the sign, it’d be better if you replace float result = ((input * (-1))); with float result = -ABS(input);