Now, the burning question is why does Swift need optionals? To understand this question, we should examine what problems optionals are designed to solve.
In most languages, it is possible to create a variable without giving it an initialized value. For example, in Objective-C, both of these lines of code are valid:
int i; MyObject *m;
Now, let's say that the MyObject
class, written in Objective-C, has the following method:
-(int)myMethodWithValue:(int)i { return i*2; }
This method takes the value passed in from the i
parameter, multiplies it by 2
, and returns the results. Let's try to call this method using the following code:
MyObject *m; NSLog(@"Value: %d",[m myMethodWithValue:5]);
Our first thought might be that this code would display Value: 10
since we are passing the value of 5
to a method that doubles the value passed in; however, this would be incorrect. In reality, this code would display Value: 0
because...