Importance of 'const' in C++

Lets declare a class 'Demo'

class Demo
{
private:
 char a;

 void TestConst(char* const pData)const
 {
  // pData = "test"; // char* const protects 
  // pData++;        // pointer!

  // a = 'a';        // const for function 
                     // protects data member.
 }
};

So, when we are working with C++, all data members irrespective of access specification, can be protected with 'const', appended to the declaration/definition.

Comments

Rahul Bhattacharjee said…

do you mean data member a becomes a constant ? as you would not be able to assign any value to it. If that is the case then you have to declare and define a value of it there itself.
Is that correct ?

March 9, 2009 at 9:17 AM

Mufti Mohammed said…

This has two aspect. First look at function signature.

First, char *const pData means pData is a const pointer to char. We can't change the pointer itself.

Second TestConst is a const function. const function does not allow any modification of member variables, though member variable(s)is/are not const.

March 10, 2009 at 1:03 AM

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