How to declare const data member in class

**chottachatri** · 05-05-2008

Hello,
why is the below declaration not working and what to do to make it a valid one?

Code:

class shape
{
 const int p;

 public:
  shape()
  {
   p=10;
  }
  void display()
  {
	cout<<p;
  }
};

**~~manav~~** · 05-05-2008

Code:

class shape
{
 const int p;

 public:
  shape()
  : p(10) 
  {
//   p=10;
  }
  void display()
  {
    cout<<p;
  }
};

RED part was wrong!
GREEN part is added by me, and is the right way to do this!

**swgh** · 05-05-2008

Just a side note, if you decalre an array size in a class, make sure you make it static.

Code:

class Foo
{
public:
   static const int ARRAY_SIZE = 10;
};

**mickey0** · 05-05-2008

Probabily you can do something like this:

Code:

Class A {
   const int _p;
public:
     A() : _p(10) { }
     //or
     A(int size) : _p(size) {}
};

Thread: How to declare const data member in class