in objective-c we can declare variable like
var a: NSString = ""
var b: NSString = ""
var c: NSString = ""
var (a,b,c): a:NSstring=("","","")
You can declare multiple constants or multiple variables on a single line, separated by commas:
var a = "", b = "", c = ""
If a stored value in your code is not going to change, always declare it as a constant with the let keyword. Use variables only for storing values that need to be able to change.
You can define multiple related variables of the same type on a single line, separated by commas, with a single type annotation after the final variable name:
var red, green, blue: Double
It is rare that you need to write type annotations in practice. If you provide an initial value for a constant or variable at the point that it is defined, Swift can almost always infer the type to be used for that constant or variable, as described in Type Safety and Type Inference.