fix an index out of bound exception in swift

An index out of bound exception in Swift occurs when you try to access an array element outside of its valid range. To fix this error, you can follow the steps below:

1. Check the array bounds: Make sure that the index you are trying to access is within the valid bounds of the array. The valid indices of an array start from 0 to the length of the array minus 1.

2. Use optional binding if applicable: If you are accessing an array element that may or may not exist, you can use optional binding to handle this scenario. This will help you avoid an index out of bound exception.

3. Use try-catch: If you are accessing an array element using a subscript and you are not sure if the subscript will be within bounds, you can use a try-catch block to handle the error that might occur.

Here's an example of how you can use try-catch block to handle an index out of bound error:

main.swift
let array = [1, 2, 3]
do {
    let element = try array.at(5)
} catch let error as IndexOutOfRangeError {
    print("\(error.localizedDescription)")
} catch {
    print("Unexpected error: \(error).")
}
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In the above code, the at(_:) method throws an IndexOutOfRangeError when the index is out of the array's bounds. The do-catch block catches the error and prints the error message. You can customize the error handling as per your requirement.