Swift Tutorial - Swift Global and Local Variables

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Scope refers to a portion of a program.

We can access variables only from the portion of the program where the variable has been declared.

Global scope variables can be accessed from anywhere in your Swift program.

Portions of the program are defined by various Swift constructs such as if statements, functions, and classes.

You will see curly brackets {} used with Swift constructs to define a scope for part of your program.

Example

The following code uses if statement as an example to demonstrate scope.

let isTrue = true

if(isTrue){
    var myString = "This is a true statement"
    println(myString)
}

The code above declares a boolean constant called isTrue and uses an if statement to test to see whether isTrue is set to a true value.

We define a scope with curly brackets {} and put the code in between the curly brackets.

myString is a variable that is local to the scoped area of if statement. We can access myString only in that scoped area.

Since isTrue is a global variable, you can use that anywhere in your program, including the scoped area after if statement.

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