Object Oriented Programming
Structures in Swift
Structures are classes which are value-typed, similar to previous variables and lets.
Structures, like classes, contain methods and properties.
Syntax
struct structureName {
//properties and methods declared here
}
//instantiating a structure, with properties (also called fields)
var structureInstance = structureName(fieldName: fieldValue)
//accessing structure public method or field
var structureInstance.structureMember
Notes
Structures cannot be inherited, deinitialized or type cast.
Because structures are value typed, when they are passed around in code, a new copy is always made of the instance.
As a guideline, structures are used when encapsulating other value types.
Example
//structure declaration
struct Circle {
var radius: Double = 0;
func area() -> Double {
return radius * radius * 3.14
}
func circumference() -> Double {
return radius * 2 * 3.14
}
}
//structure instance
var wheel = Circle(5.3)
print "The area of the wheel is \(wheel.area())"