+= operator creating error

Swift Programming: The Big Nerd Ranch Guide (2nd E 5. Switch
1

Here’s the error I’m getting

Playground execution failed: error: Switch.playground:3:17: error: variable ‘errorString’ passed by reference before being initialized
errorString += " Informational, 1xx."

this doesn’t happen if I’m just using “=” as an operator

any ideas? Has something changed in swift that doesn’t require the addition operator?

2

That error message is saying the variable errorString must be initialized before being passed by reference to a function.

You probably have something that looks like this:

func giggleAndHoot (_ s: inout String) {
    s += "Giggle & Hoot: ..."
}

var jimmyGiggle : String

giggleAndHoot (&jimmyGiggle)   // Error: jimmyGiggle not initialized!

Intialize the variable first:

var jimmyGiggle : String

jimmyGiggle = ""

giggleAndHoot (&jimmyGiggle)  // Good: jimmyGiggle initialized
3

Thank you I’ll try that