Exceeding String Bounds in Swift in Swift

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

Remember, the characters of a string are normally indexed from 0 to count - 1.

Any index which is strictly greater than count - 1 is invalid.

When you try to access a character with an invalid index, Swift causes a fatal error: Index out of range:

var car = "ford"

// Valid indices: 0, 1, 2, 3
print(Array(car)[0]) // Output: f
print(Array(car)[3]) // Output: d

// Invalid indices: 4, 30
print(Array(car)[4]) // Fatal error: Index out of range
print(Array(car)[30]) // Fatal error: Index out of range

This code would cause a Fatal error: Index out of range

In conclusion, we always want to double check our code to make sure that we don't exceed one string's bounds in our programs.

Assignment
Follow the Coding Tutorial and let's practice with string bounds!

Hint
Look at the examples above if you get stuck.