Operators in Objective C and Swift

Common for Objective C and Swift

• Assignment Operator ( = )
• Arithmetic Operator
• addition +,
• Subtraction -, 
• Multiplication *,  
• Division /
• Remainder (Modulo) Operator %
• Unary plus operator (+), Unary minus operator (-), unary operator is prepended directly on the value it operates on.
• compound assignment/short hand operators (x+=y, x-=y, x*=y, x/=y, x%=y, x&=y, x|=y, x^=y)
• Increment (++) & decrement operator (—) {int x=9, int y: y= ++x , y = - - x } (Removed in Swift 3)
• Relational/Comparison operators 
• Equal to (a == b)
• Not equal to (a != b)
• Greater than (a > b)
• Less than (a < b)
• Greater than or equal to (a >= b)
• Less than or equal to (a <=  b)
• Logical Operator 
• Logical Not (!a)
• Logical AND (a && b)
• Logical OR (a || b)
• Ternary Conditional Operator ( if condition? expression 1 : expression 2 )

Swift Only

• Range Operator 
• Closed Range Operator '1…10', includes 1 and 10 in this range.
• Half Open Range Operator '1..~10 , includes 1 but not 10
• Nil-Coalescing Operator (x??y)

The nil-coalescing operator (x ?? y) unwraps an optional x if it contains a value, or returns a default value y if x is nil. The expression a is always of an optional type. The expression y must match the type that is stored inside x.

The nil Coalescing operator is shorthand for the below code:

x != nil ? x! : y

The code above uses the ternary conditional operator and forced unwrapping (x!) to access the value wrapped inside a when x is not nil, and to return x otherwise. The nil-coalescing operator provides a more elegant way to encapsulate this conditional checking and unwrapping in a concise and readable form.