How to write a function in Swift that prints prime #s

App Development
1

I am super new to programming and I am still struggling with prime number problem. I would appreciate some guidance.

How can I create a function that prints prime numbers .

Thank you!

2

Welcome back @jtalavera714 !

Here you go. Just update the end number and if you want the non-prime number, un-comment that line.

Blessings,
—Mark

func isPrime() {
    
   let numbers = 1...100
   for number in numbers {
           if (number % 2 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 3 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 4 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 5 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 6 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 7 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 8 == 0) {
//               print("\(number)'s not prime")
           } else if (number % 9 == 0) {
//               print("\(number)'s not prime")
           } else {
               print("\(number) IS prime" )
       }
    }
   }
       
isPrime()
3

If you want to check a single number you can do something like this:

func isItPrime(_ n: Int) {
    
        var isPrime = true
        
        if n == 1 {
            isPrime = false
        }
        if n != 2 && n != 1 {
            
            for i in 2 ..< n {
                
                if n % i == 0{
                    
                    isPrime = false
                }
            }
        }
        
        if isPrime {
            print("\(n) is prime!")
        } else {
            print("\(n) is not prime!")
        }
    }

print(isItPrime(2))

Blessings,
—Mark

4

I appreciate the response . Thank you very much. This really breaks it down for me.