Example of Swift comments (eg., `MARK`, `TODO`, `FIXME`), `#warning` macro and `#error` macro

comment_mark_warning_error_example.swift

// MARK: Feature One (No divider)

class FeatureOne {}

// MARK: - Class Two start (Top divider)

class FeatureTwo {}

// MARK: Class Two end - (Bottom divider)

class FeatureThree {}
class FeatureFour {}

// MARK: - With top and bottom divider -

class FeatureFive {
    // TODO: Example Todo comment (Use `-` same as `MARK` for divider)

    // FIXME: Example Fix me comment (Use `-` same as `MARK` for divider)
}

// Here is a <#placeholder#> example.

#warning("Example warning")

#error("Example error")