How to do it...

Let's use an if/else control flow statement to write a function to return the right pool ball type:

1. Create an enum to describe the possible ball types:

enum PoolBallType { 
    case solid 
    case stripe 
    case black 
}

2. Create the method that will take an Int and return PoolBallType:

func poolBallType(forNumber number: Int) -> PoolBallType { 
    if number < 8 { 
        return .solid 
    } else if number > 8 { 
        return .stripe 
    } else { 
        return .black 
    } 
}

3. Use this function and test that we get the expected results:

let two = poolBallType(forNumber: 2) // .solid 
let eight = poolBallType(forNumber: 8) // .black 
let twelve = poolBallType(forNumber: 12) // .stripe