Hello,

In the video he uses the same constant name in and out of the function and he doesn't get an error. Why?

Question

IN the video he uses the same constant name inside and outside the function and the code runs with no errors. Does it mean that the variables and constants inside functions are completely independent from the rest of the code?

Martin Wildfeuer · Accepted Answer

Let me try to explain:
Variables defined outside a function are accessible within a function.
Variables defined within a function are only accessible within the scope of this function.
Variables defined within a function are not accessible by other functions.
You can still pass variables between functions as a parameter. (Passed by value, changes will not affect the original variable, though)
Also have a look at "inout" at Apple Docs (https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Functions.html)
```Example1.swift
// Defined "global" and available
// in all functions
let test = "Test"
func testing() {
    // test is only accessible within this function
    // You now cannot access the test variable
    // defined outside this function. This is called
    // shadowing.
    let test = "InternalTest"
}
```
With classes it is the same, although you can also access the property of a class, even if "shadowed" by explicitly referring to it with self
```Example2.swift
class TestClass {
    var test = "Test"
func testing() {
    let test = "InternalTest"
    self.test = test
}
}
```
Hope that is not too confusing :)

Welcome to the Treehouse Community

Looking to learn something new?

Jose Patarroyo

Jose Patarroyo

Hello, In the video he uses the same constant name in and out of the function and he doesn't get an error. Why?

1 Answer

Martin Wildfeuer

Martin Wildfeuer