What's the use of const here

Question

in

int salary() const { return mySalary; }

as far as I understand const is for this pointer, but I\'m not sure. Can any one tell me what is the us

Answer 1

It just guarantees that calling salary() doesn't change the object state. IE, it can be called with a const pointer or reference.

Answer 2

When the function is marked const it can be called on a const pointer/reference of that class. In effect it says This function does not modify the state of the class.

Answer 3

It's a const member function. It's a contract that the function does not change the state of the instance.

more here: http://www.fredosaurus.com/notes-cpp/oop-memberfuncs/constmemberfuncs.html

Answer 4

It means that function can be called on a const object; and inside that member function the this pointer is const.

Answer 5

Sounds like you've got the right idea, in C++ const on a method of an object means that the method cannot modify the object.

For example, this would not be allowed:

class Animal {
   int _state = 0;

   void changeState() const { 
     _state = 1;
   }
}

Answer 6

A const after function of a class, means this function would not modify any member objects of this class. Only one exception, when the member variable is marked with Mutable.