do{ 
let someValue1:Optional<String> 
//print(someValue1) // error: constant 'someValue1' used before being initialized 
var someValue11:Optional<String> 
// print(someValue11) // error: variable 'someValue11' used before being initialized 
let someValue2:String? 
// print(someValue2) //error: constant 'someValue2' used before being initialized 
var someValue22:String? 
print(someValue22) // Compiler happy. Why? What is the technical reason why this should work. 

// Now consider the following type of optional. 
var someValue33:String!
print(someValue33 + "") // Boom Crash. Implicit initialization here is actually dangerous. 
}