iOS repl.it - Switch Challenge Solution

switch.swift

////Don't change this
var aNumber =  Int(readLine()!)! 

func dayOfTheWeek(day: Int) {
  
  //Write your code inside this function.
  switch day {
    case 1:
    print("Monday")
    case 2:
    print("Tuesday")
    case 3:
    print("Wednesday")
    case 4:
    print("Thursday")
    case 5:
    print("Friday")
    case 6:
    print("Saturday")
    case 7:
    print("Sunday")
    default:
    print("Error")
  }
  
  
}

//Don't change this
dayOfTheWeek(day: aNumber)

Why do we need the statement : let aNumber = Int(readLine()!)! in every code? because whenever I apply it on my playground. It does not work and always show this.

When I take it out of my code, it works properly (as below). Can anyone please explain that to me? Many thanks!!

I have the same question what does let aNumber = Int(readLine()!)! do? Thanks

Let me try to answer,
The readLine() is used to read the input from the user, which is in this case is from the keyboard. So if you need an input from the keyboard, use this function. If not, just delete it and replace this code :

dayOfTheWeek(day: aNumber) to dayOfTheWeek(day: 5) // or whatever you want

In this case we need an input to match with the cases from switch statement, that's why we need readLine(). Since the readLine() will return an optional, we need to unwrap it.

For example :

let aNumber = readLine() // it will return optional on the terminal. When you type "hello" from the keyboard, it will return "optional(hello)".

To solve it, add "!" after parentheses.

let aNumber = readLine()! // it will unwrap the value, and return it instead of returning "optional(value)".

Because we need a number from the input, the code should like this :

let aNumber = Int(readLine()!)! // add "!" to unwrap the value, so it will not return an "optional(value)".

But why it still throw an error even the code is correct? That's because this readLine() function need a terminal to work, and Playground doesn't support it. Instead to create a playfround file, create a new macOS project and choose command line tool like this :

It will not show an error anymore because Command Line Tool support the terminal environment to read user input.
Hope it will help you 👍

Why do we need the statement : let aNumber = Int(readLine()!)! in every code? because whenever I apply it on my playground. It does not work and always show this.

When I take it out of my code, it works properly (as below). Can anyone please explain that to me? Many thanks!!

https://gist.github.com/TheMuellenator/ceed75150b5f7127c8bf38b3564e7ca3#gistcomment-3687911

Hope it will help you 👍

So basically I just did a reset on the challenge page and then just tried again.

Only use this.

switch day {
case 1:
print("Monday")
case 2:
print("Tuesday")
case 3:
print("Wednesday")
case 4:
print("Thursday")
case 5:
print("Friday")
case 6:
print("Saturday")
case 7:
print("Sunday")
default:
print("Error")

oh my....as usual it would give me errors again, while working in my playground....so came here to check...you all have the same, I mean this one is quite easy....in the end I didn't copy and paste the last }...(smacks own head)

This worked for me
{ switch day { case 1: print ("Monday")
case 2: print ("Tuesday")
case 3: print ("Wednesday")
case 4: print ("Thursday")
case 5: print ("Friday")
case 6: print ("Saturday")
case 7: print ("Sunday")
default: print ("Error")
}
}

////Don't change this
var aNumber = Int(5)

func dayOfTheWeek(day: Int) {
switch day {
case 1:print("Monday")
case 2:print("Tuesday")
case 3:print("Wednesday")
case 4:print("Thursday")
case 5:print("Friday")
case 6:print("Saturday ")
case 7:print("Sunday ")
default:print("Error")
}
}
//Try out some different numbers here
//Don't copy the line below into Udemy

dayOfTheWeek(day: 5)

////Don't change this

func dayOfTheWeek(day: Int) {
let day = Int.random(in: 1...7)
switch day {
case 1:
print("monday")
case 2:
print("tuseday")
case 3:
print("wansday")
case 4:
print("tuseday")
case 5:
print("friday")
case 6:
print("seterday")
case 7:
print("sunday")
default:
print("error")
}

}
dayOfTheWeek(day: 4)
//Try out some different numbers here
//Don't copy the line below into Udemy

I still keep getting error. what's wrong with my code?

var aNumber =  Int(readLine()!)! 

// Function to determine the corresponding day of the week. It takes an integer day as a parameter
func dayOfTheWeek(day: Int) {
    
    switch day {
    case 1:
        print("Monday")
    case 2:
        print("Tuesday")
    case 3:
        print("Wednesday")
    case 4:
        print("Thursday")
    case 5:
        print("Friday")
    case 6:
        print("Saturday")
    case 7:
        print("Sunday")
    default:
        print("Error")
    }
}

// We call the function with the user input integer aNumber as the argument and it prints the day of the week to the console
dayOfTheWeek(day: aNumber)

////Don't change this
var aNumber = Int(readLine()!)!

func dayOfTheWeek(day: Int) {

//Write your code inside this function.

switch(day) {
case 1:
print("Monday")
case 2:
print("Tuesday")
case 3:
print("Wednesday")
case 4:
print("Thursday")
case 5:
print("Friday")
case 6:
print("Saturday")
case 7:
print("Sunday")
default:
print("Error")
}
}

This is how I did it, it was super fun.

var aNumber = 1 // you can insert your own number here

func dayOfTheWeek(day: Int) {
    
    let daysArray = ["Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"]
    
    switch day {
    case 1...daysArray.count:
        print(daysArray[day - 1])
    default:
        print("Error")
    }
    
    
    
}

dayOfTheWeek(day: aNumber)