How to turn decimal into a fraction - Swift

Question

I have a fraction calculator and when I calculate it, it turns into a decimal. I want to turn it into a fraction. I don't know how to do it in code but I tried separating the calculations but it wouldn't work here is the code with a screenshot of my storyboard https://www.dropbox.com/s/fmapxaou49zap05/iOS%20Simulator%20Screen%20Shot%20Oct%2015%2C%202014%2C%209.37.43%20PM.png?dl=0

        //Adding Function
        changingSignsLabel.text = "+"
        let firstDenomInTextField:Double! = (firstDenominatorTextField.text as NSString).doubleValue
        let firstNumInTextField:Double! = (firstNumeratorTextField.text as NSString).doubleValue
        let firstWholeInTextField:Double! = (firstWholeNumberTextField.text as NSString).doubleValue

        let secondDenomInTextField:Double! = (secondDenominatorTextField.text as NSString).doubleValue
        let secondNumInTextField:Double! = (secondNumeratorTextField.text as NSString).doubleValue
        let secondWholeInTextField:Double! = (secondWholeNumberTextField.text as NSString).doubleValue

        var firstStep = firstDenomInTextField! * firstWholeInTextField! / firstDenomInTextField!

        var secondStep = firstStep + firstNumInTextField! / firstDenomInTextField!

        var thirdStep = secondDenomInTextField! * secondWholeInTextField! / secondDenomInTextField!
        var fourthStep = thirdStep + secondNumInTextField! / secondDenomInTextField!

        var calculatedAnswer = (secondStep + fourthStep)

        answerLabel.hidden = false

        answerLabel.text = "\(calculatedAnswer)"

If you have any questions or concerns please comment them down below

Thank you for your help

Answer 1

For this to work every time, you want to use the Euclidian Algorithm, which in swift looks like this:

func simplify(top:Int, bottom:Int) -> (newTop:Int, newBottom:Int) {

    var x = top
    var y = bottom
    while (y != 0) {
        var buffer = y
        y = x % y
        x = buffer
    }
    var hcfVal = x
    var newTopVal = top/hcfVal
    var newBottomVal = bottom/hcfVal
    return(newTopVal, newBottomVal)
}

You should just be able to add this to your program, then call it with:

simplify(5,10)

...returning 1 and 2. Hope this helps anyone else trying to find a simpler answer to this question.

Answer 2

Updated Answer

I wrote you a demo app:

Swift Source Code:

Put this inside your view controller.

var numeratorField:UITextField?;
var denominatorField:UITextField?;
var equalButton:UIButton?;
var wholeNumberLabel:UILabel?;
var numeratorLabel:UILabel?;
var denominatorLabel:UILabel?;
var dividerLine:UIView?;

var appName:UILabel?;
var instructions:UILabel?;


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    initViews();
    initConstraints();
}

// ---------------------------------------------------------------------
// MARK: Interface Setup
// ---------------------------------------------------------------------

func initViews()
{
    self.numeratorField = UITextField();
    self.numeratorField?.layer.cornerRadius = 5.0;
    self.numeratorField?.layer.borderWidth = 1.0;
    self.numeratorField?.textAlignment = NSTextAlignment.Center;

    self.denominatorField = UITextField();
    self.denominatorField?.layer.cornerRadius = 5.0;
    self.denominatorField?.layer.borderWidth = 1.0;
    self.denominatorField?.textAlignment = NSTextAlignment.Center;

    self.equalButton = UIButton();
    self.equalButton?.setTitle("=", forState: UIControlState.Normal);
    self.equalButton?.addTarget(self, action: "calculateAnswer", forControlEvents: UIControlEvents.TouchUpInside);
    self.equalButton?.setTitleColor(UIColor.darkGrayColor(), forState: UIControlState.Normal);
    self.equalButton?.layer.cornerRadius = 5.0;
    self.equalButton?.backgroundColor = UIColor.lightGrayColor();

    self.wholeNumberLabel = UILabel();
    self.wholeNumberLabel?.textAlignment = NSTextAlignment.Right;
    self.wholeNumberLabel?.font = UIFont(name: "HelveticaNeue", size: 20);

    self.numeratorLabel = UILabel();
    self.numeratorLabel?.textAlignment = NSTextAlignment.Center;
    self.numeratorLabel?.font = UIFont(name: "HelveticaNeue", size: 14);

    self.denominatorLabel = UILabel();
    self.denominatorLabel?.textAlignment = NSTextAlignment.Center;
    self.denominatorLabel?.font = UIFont(name: "HelveticaNeue", size: 14);

    self.dividerLine = UIView();
    self.dividerLine?.backgroundColor = self.numeratorLabel!.textColor;
    self.dividerLine?.alpha = 0;

    self.appName = UILabel();
    self.appName?.text = "Fraction App";
    self.appName?.font = UIFont(name: "HelveticaNeue-Bold", size: 24);
    self.appName?.textAlignment = NSTextAlignment.Center;

    self.instructions = UILabel();
    self.instructions?.textAlignment = NSTextAlignment.Center;
    self.instructions?.text = "Enter a value in the numerator and denominator field, then press the equal sign to see the answer";
    self.instructions?.numberOfLines = 0;
    self.instructions?.lineBreakMode = NSLineBreakMode.ByWordWrapping;

    self.view.addSubview(self.numeratorField!);
    self.view.addSubview(self.denominatorField!);
    self.view.addSubview(self.equalButton!);
    self.view.addSubview(self.wholeNumberLabel!);
    self.view.addSubview(self.numeratorLabel!);
    self.view.addSubview(self.denominatorLabel!);
    self.view.addSubview(self.dividerLine!);
    self.view.addSubview(self.appName!);
    self.view.addSubview(self.instructions!);
}

func initConstraints()
{
    self.appName?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.numeratorField?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.denominatorField?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.equalButton?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.wholeNumberLabel?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.numeratorLabel?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.denominatorLabel?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.dividerLine?.setTranslatesAutoresizingMaskIntoConstraints(false);
    self.instructions?.setTranslatesAutoresizingMaskIntoConstraints(false);

    var views:NSMutableDictionary = NSMutableDictionary();
    views.setValue(self.appName, forKey: "appName");
    views.setValue(self.numeratorField, forKey: "numeratorField");
    views.setValue(self.denominatorField, forKey: "denominatorField");
    views.setValue(self.equalButton, forKey: "equalButton");
    views.setValue(self.wholeNumberLabel, forKey: "wholeNumberLabel")
    views.setValue(self.numeratorLabel, forKey: "numeratorLabel");
    views.setValue(self.denominatorLabel, forKey: "denominatorLabel");
    views.setValue(self.dividerLine, forKey: "dividerLine");
    views.setValue(self.instructions, forKey: "instructions");

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[appName]|", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-50-[appName]", options: nil, metrics: nil, views: views));

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-20-[instructions]-20-|", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[instructions]-100-|", options: nil, metrics: nil, views: views));

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-35-[numeratorField(75)]-10-[denominatorField(==numeratorField)]-10-[equalButton]-10-[wholeNumberLabel(>=20)]-2-[dividerLine(15)]", options: nil, metrics: nil, views: views));

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[numeratorField(50)]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[denominatorField(==numeratorField)]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[equalButton(==numeratorField)]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[wholeNumberLabel(==numeratorField)]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[numeratorLabel]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[denominatorLabel]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[dividerLine(1)]", options: nil, metrics: nil, views: views));

    self.view.addConstraint(NSLayoutConstraint(item: self.numeratorLabel!, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.Equal, toItem: self.wholeNumberLabel, attribute: NSLayoutAttribute.Right, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.denominatorLabel!, attribute: NSLayoutAttribute.Left, relatedBy: NSLayoutRelation.Equal, toItem: self.wholeNumberLabel, attribute: NSLayoutAttribute.Right, multiplier: 1.0, constant: 0.0));

    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[numeratorLabel(==wholeNumberLabel)]", options: nil, metrics: nil, views: views));
    self.view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:[denominatorLabel(==wholeNumberLabel)]", options: nil, metrics: nil, views: views));



    self.view.addConstraint(NSLayoutConstraint(item: self.numeratorField!, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.denominatorField!, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.equalButton!, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.wholeNumberLabel!, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.dividerLine!, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));

    self.view.addConstraint(NSLayoutConstraint(item: self.numeratorLabel!, attribute: NSLayoutAttribute.Bottom, relatedBy: NSLayoutRelation.Equal, toItem: self.wholeNumberLabel, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
    self.view.addConstraint(NSLayoutConstraint(item: self.denominatorLabel!, attribute: NSLayoutAttribute.Top, relatedBy: NSLayoutRelation.Equal, toItem: self.wholeNumberLabel, attribute: NSLayoutAttribute.CenterY, multiplier: 1.0, constant: 0.0));
}

func getLowestCommonDenominator(Numerator numerator:Int, Denominator denominator:Int) -> Int
{
    var finalDenominator = denominator;

    //println("\(numerator) / \(finalDenominator) = \(numerator % finalDenominator)");

    if(numerator % 2 == 0 && finalDenominator % 2 == 0) // even number
    {
        return self.getLowestCommonDenominator(Numerator: numerator / 2.0, Denominator: finalDenominator / 2.0);
    }
    else if(numerator % 3 == 0 && finalDenominator % 3 == 0) // odd number
    {
        return self.getLowestCommonDenominator(Numerator: numerator / 3.0, Denominator: finalDenominator / 3.0);
    }
    else // prime number, always have a remainder
    {
        //println("lowest common denominator = \(finalDenominator)");

        return finalDenominator;
    }
}

func calculateAnswer()
{
    // prevent division by zero
    if(self.denominatorField?.text == "0")
    {
        var alert:UIAlertView = UIAlertView(title: "Division By Zero", message: "Divide by zero yields undefined value", delegate: self, cancelButtonTitle: "OK");
        alert.show();

        return;
    }

    // clear previous values;
    self.wholeNumberLabel?.text = "";
    self.numeratorLabel?.text = "";
    self.denominatorLabel?.text = "";

    var numeratorString:NSString = self.numeratorField!.text;
    var denominatorString:NSString = self.denominatorField!.text;

    if (numeratorString.length == 0 || denominatorString.length == 0)
    {
        //var alert:UIAlertView = UIAlertView(title: "Input Missing", message: "Enter a value for numerator and denominator then press the equal sign to get the answer", delegate: nil, cancelButtonTitle: "OK", otherButtonTitles: nil, nil);

        var alert:UIAlertView = UIAlertView(title: "Input Missing", message: "Enter a value for numerator and denominator then press the equal sign to get the answer", delegate: nil, cancelButtonTitle: "OK");

        alert.show();
    }
    else
    {
        var shouldShowWholeParts:Bool = false;
        var shouldShowFractionParts:Bool = false;

        var numerator:Int = self.numeratorField!.text.toInt()!;
        var denominator:Int = self.denominatorField!.text.toInt()!;

        var finalNumerator = numerator;
        var finalDenominator = self.getLowestCommonDenominator(Numerator: numerator, Denominator: denominator);

        if(finalDenominator < denominator)
        {
            denominator = finalDenominator;
            numerator = numerator / finalDenominator;
        }

        var wholeNumbers:Int = numerator / denominator;
        var remainder:Int = numerator % denominator;

        //println("wholeNumbers = \(wholeNumbers), remainder = \(remainder)");
        //println("\(denominator) % \(remainder) = \(denominator % remainder)");

        if(wholeNumbers != 0)
        {
            shouldShowWholeParts = true;
        }
        else
        {
            shouldShowWholeParts = false;
        }

        if(remainder > 0)
        {
            // see if we can simply the fraction part as well
            if(denominator % remainder == 0) // no remainder means remainder can be simplified further
            {
                finalDenominator = denominator / remainder;
                finalNumerator = remainder / remainder;
            }
            else
            {
                finalNumerator = remainder;
                finalDenominator = denominator;
            }

            shouldShowFractionParts = true;
        }
        else
        {
            shouldShowFractionParts = false;
        }

        var answer:NSString?;

        if(wholeNumbers > 0 && remainder > 0)
        {
            answer = NSString(format: "\(wholeNumbers) \(finalNumerator)/\(finalDenominator)");

            // prints out whole number and fraction parts
            //println("Simplified fraction of \(numerator)/\(denominator) = \(wholeNumbers) \(finalNumerator)/\(finalDenominator)");
        }
        else if (wholeNumbers > 0 && remainder == 0)
        {
            answer = NSString(format: "\(wholeNumbers)");

            // prints out whole number only
            //println("Simplified fraction of \(numerator)/\(denominator) = \(wholeNumbers)");
        }
        else
        {
            answer = NSString(format: "\(finalNumerator)/\(finalDenominator)");

            // prints out fraction part only
            //println("Simplified fraction of \(numerator)/\(denominator) = \(finalNumerator)/\(finalDenominator)");
        }

        if(shouldShowWholeParts)
        {
            self.wholeNumberLabel?.text = NSString(format: "\(wholeNumbers)");
        }

        if(shouldShowFractionParts)
        {
            self.numeratorLabel?.text = NSString(format: "\(finalNumerator)");
            self.denominatorLabel?.text = NSString(format: "\(finalDenominator)");
            self.dividerLine?.alpha = 1;
        }
        else
        {
            self.dividerLine?.alpha = 0;
        }


    }
}

Original Answer

Is this what you're looking for?

Results:

Simplified fraction of 7/8 = 7/8
Simplified fraction of 12/8 = 1 1/2
Simplified fraction of 5/16 = 5/16
Simplified fraction of 342/23 = 14 20/23
Simplified fraction of 129/72 = 1 57/72

Source Code:

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    printSimplifiedFraction(Numerator: 7, Denominator: 8);
    printSimplifiedFraction(Numerator: 12, Denominator: 8);
    printSimplifiedFraction(Numerator: 5, Denominator: 16);
    printSimplifiedFraction(Numerator: 342, Denominator: 23);
    printSimplifiedFraction(Numerator: 129, Denominator: 72);
}

func printSimplifiedFraction(Numerator numerator: Int, Denominator denominator:Int)
{
    var finalNumerator = numerator;
    var finalDenominator = denominator;

    var wholeNumbers:Int = numerator / denominator;
    var remainder:Int = numerator % denominator;

    //println("wholeNumbers = \(wholeNumbers), remainder = \(remainder)");
    //println("\(denominator) % \(remainder) = \(denominator % remainder)");

    if(remainder > 0)
    {
        // see if we can simply the fraction part as well
        if(denominator % remainder == 0) // no remainder means remainder can be simplified further
        {
            finalDenominator = denominator / remainder;
            finalNumerator = remainder / remainder;
        }
        else
        {
            finalNumerator = remainder;
            finalDenominator = denominator;
        }
    }

    if(wholeNumbers > 0 && remainder > 0)
    {
        // prints out whole number and fraction parts
        println("Simplified fraction of \(numerator)/\(denominator) = \(wholeNumbers) \(finalNumerator)/\(finalDenominator)");
    }
    else if (wholeNumbers > 0 && remainder == 0)
    {
        // prints out whole number only
        println("Simplified fraction of \(numerator)/\(denominator) = \(wholeNumbers)");
    }
    else
    {
        // prints out fraction part only
        println("Simplified fraction of \(numerator)/\(denominator) = \(finalNumerator)/\(finalDenominator)");
    }
}

Answer 3

Unfortunately there is not framework you can import to display a fraction in swift or Xcode. What I would recommend is using the same method you used in your storyboard: Have two UILabelView's, one on top of each other, with a line between them.

Instead of calculating the decimal, use basic math to find the numerator and denominator and display them on the top and bottom of the UILabelView.

This method will require changing your program at a fundamental level, however it will work.