Constants in C++
There are two ways of creating constants in C++
1. Using the qualifier const
2. Defining a set of integer constants using enum keyword
Any variable declared as const cannot be modified by the program in any way . The const modifier is used to make a variable value unmodifiable. Any attempt to change the value will result in a compile-time error.
For example, const int size = 18 ;
size++ ; //error: cannot modify
C++ requires a const to be initialized.
For example, const int number ; // error uninitialized const
Another method of naming integer constants is as follows :
enum { A, B, C } ;
This defines A, B, C as integer constants with values 0, 1, and 2 respectively. This is equivalent to :
const int A = 0 ;
const int B = 1 ;
const int C = 2 ;
We can also assign values to A, B, and C explicitly.
enum { A = 10, B = 12, C = 20 } ;
Such values can be any integer values.
