0Objective C Provides a way to declare constant using Const keyword.
In Objective C we often use #define for declaring a macro.
Swift the way to declare constants is different from objective C.
Let is used to declare a constant in Swift Language.
let a: String="hello World!"
Let tells the compiler that 'a' is the name of the variable which is constant Constant.
String tell the type of the constant that a stores.
Declaring constants and using then is similar to using immutable classes like NSString,NSArray etc.
NSString *a=@"hello World!"
In the above line a is pointer to NSString address which is Immutable i.e whose address content cant be changed.
Let me describe the difference between using const * and *const pointers.
int a = 10; int b = 15;
int *const ptr = &a;
*ptr = 20; // OK. a is now 20.
ptr = &b; // Error, ptr is a constant.
ptr = &b; // Error, ptr is a constant.
The above declaration should be read from left to right. The above code declares a const pointer to int.
Pointer ptr can't be made to point do different variable.
