swift - use backslash to add the value in the string

There’s an even simpler way to include values in strings: Write the value in parentheses, and write a backslash (\) before the parentheses. This is known as string interpolation.

1. let apples = 3
2. let oranges = 5
3. let appleSummary = "I have \(apples) apples."
4. let fruitSummary = "I have \(apples + oranges) pieces of fruit."