Making Apppcations with Swift

In this chapter, we will create two new Apppcations using Swift.

First Apppcation – "Guess the Number"

In this section, we will create an Apppcation called "Guess the number". To make this apppcation, create a new iOS Single View Apppcation and name it whatever you want.

Cpck on the main.storyboard and select your main view.

Add a text label → Change the text to “Guess the number”. Change the color, size properties and make it as per your requirement.

Add an Input field, stretch to full view.

Add a button and name it “Guess.

Add one more label, stretch it, and clear the text box.

This is how your view should look pke after adding all the elements.

Now Switch to assistant editor and Cpck on drag from your UI element to view controller file, then connect the text field as an outlet and name it userInput. Similarly,

Connect empty label as outlet and name it as resultLabel.

Connect Guess button as action and name it as guessButtonPressed.

What is the logic?

The logic is simple, we will generate random numbers between 0-9 and see if that is equal to the number the user entered, or not. If it is equal, we will show "you are right", else we will show "you are wrong!".

Applying the logic

To generate a random number between 0-9, we will use the following command.

let rollIt = String(arc4random_uniform(10))

Then we will use the following logic to check whether it is same as the user input or not.

if userInput.text == rollIt { 
   resultLabel.text = "You re right!" 
} else { 
   resultLabel.text = "Wrong! It was a " + rollIt + "." 
}

This is how your final logic in button action function will look pke.

@IBAction func guessButtonPressed(_ sender: Any) { 
   let rollIt = String(arc4random_uniform(10))  
   if userInput.text == rollIt { 
      resultLabel.text = "You re right!" 
   } else { 
      resultLabel.text = "Wrong! It was a " + rollIt + "." 
   } 
} 

Your final apppcation should look pke this now.

Let us now run our Apppcation and check its output. The opening screen should look as follows −

Next, feed a number in the input area.

Let’s feed another number and check its output −

We have completed one more Apppcation. Try to run this apppcation, and enter different inputs.

Second Apppcation – "Is It Prime"

In this apppcation, we will be taking an input from the user and we will check whether that number is prime or not −

Layout − Similar to the previous apppcation, we need an input, a button and an output label.

Challenges − Create the UI and connect the elements to code. Also, try if you can create the complete project yourself. If you managed to create it by yourself, then it is great and you are doing excellent with iOS Development.

If you could not manage, do not worry. Look at the following image and try to do the same.

Try to create a view pke this, if you are not able to do it yet, please read the previous section where we have developed a Guess Game.

What is the Logic?

Prime numbers are the numbers that cannot be spanided by any other number except 1 and the number itself.

Example − 7 is a prime number as any other number except 1 and 7 cannot spanide it.

How to Implement?

Try to write a code for checking prime numbers. Then take the user input and see if that is a prime or not. If yes, then show prime; otherwise show not prime in your result label.

Here is the code to check whether a suppped number is "prime" or not −

@IBAction func isItPrimeButtonPressed(_ sender: Any) { 
   if let userEnteredString = userInput.text { 
      let userEnteredInteger = Int(userEnteredString) 
      if let number = userEnteredInteger { 
         var isPrime = true 
         if number == 1 { 
            isPrime = false 
         } 
         var i = 2 
         while i < number { 
            if number % i == 0 { 
               isPrime = false 
            } 
            i += 1 
         } 
         
         if isPrime { 
            resultLabel.text = "yes. (number) is prime!" 
         } else { 
            resultLabel.text = "No. (number) is not prime" 
         } 
      } else { 
         resultLabel.text = "Please enter a positive whole number"                 
      } 
   } 
} 

This is how your button action should look pke. Following is the image of the final code and view −

This is how your running apppcation should look pke if you followed the procedure.

Now, let us test our Apppcation by supplying input values −