CODEWITHSUNDEEP
arraysswift
Redman
Redman

Reputation: 13

How to start from the beginning when you reached end of index of array range in swift?

Hey guys I'm a beginner of learning swift. In my program I have an array which has 49 items and I want to print out by labels every item one by one on screen by swiping action (left to right and right to left). However when I reach the end of my array I get fatal error because of out array index range.

I tried to use a counter variable in order to count swipes and set its index number to 0 when it reaches 49 but it does not work. How can I cope with this? Thanks.

if swipeCounter == 49{
    swipeCounter = 0
}


firstCell.text = String(numberList[swipeCounter])
secondCell.text = String(numberList[swipeCounter + 1])
thirdCell.text = String(numberList[swipeCounter + 2])

swipeCounter = ++swipeCounter

println(swipeCounter)

Upvotes: 0

Views: 504

Answers (1)

Rajeev Bhatia
Rajeev Bhatia

Reputation: 2994

The error is probably occurring because you are checking the value of swipeCounter and then increasing it. So even if swipeCounter is 48, it will not be set to 0 and an attempt to access swipeCounter + 2 i.e. 50 will result in a crash. Plus I am not really a big fan of using hardcoded lengths in my code.

I would suggest doing this

firstCell.text = String(numberList[swipeCounter % numberList.count])
secondCell.text = String(numberList[(swipeCounter + 1) % numberList.count])
thirdCell.text = String(numberList[(swipeCounter + 2) % numberList.count])

the modulus operator should just handle any index overflows and replacing 49 with numberList.count will also be a good move if the array length changes.

Hope this helps!

Upvotes: 1

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