Exceeding static array's bounds in Swift

When accessing array data with indices, the most common problem we can run into is exceeding the array's bounds.

Remember, the items of an array are indexed from 0 to count - 1. Any index which is not in this range is invalid.

When you try to access an item with an invalid index, Swift stops the program with a fatal error (it is not an exception you can catch):

var ourArray = [50, 40, 30]

// Valid indices: 0, 1, 2
print(ourArray[0]) // Output: 50
print(ourArray[2]) // Output: 30

// Invalid indices: 3, 30, -1
print(ourArray[3]) // Fatal error: Index out of range
print(ourArray[30]) // Fatal error: Index out of range
print(ourArray[-1]) // Fatal error: Index out of range

As programmers, we always want to make sure that we don't exceed one array's bounds in our programs.

Assignment
Follow the Coding Tutorial and let's play with some arrays.

Hint
Look at the examples above if you get stuck.