Why can't static data members initialized in an constructor's initialization list while it can be done in the constructor's definition ?
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1How do you propose you initialize a data member in the constructor's body?Qaz– Qaz2013-04-10 05:35:14 +00:00Commented Apr 10, 2013 at 5:35
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3 Answers
You got it wrong. They can be initialized in a single translation unit outside the class definition* and they can be assigned to in the constructor.
You can only initialize current non-static class member in the initialization list of the constructor.
*Exceptions apply
Static members are in class scope i.e they are class variable not instance variable.We initialize instances by constructor. As static variable are not for the instance but for the entire class so static variables are not initialized by constructor . Thanks
answered Apr 10, 2013 at 6:42
Tunvir Rahman Tusher
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Lets try this more specific
#include <iostream>
using namespace std;
class classWithStaticVariable
{
static int aStaticVariable;
int aNormalInstanceVariable;
public:
classWithStaticVariable(int aParameter)
{
aNormalInstanceVariable=aParameter;
aStaticVariable=aNormalInstanceVariable;/////It is possible to assign value to static data member in constructor but not possible to init it.
}
void aTestFunctionJustToPrint()
{
cout<<aStaticVariable<<aNormalInstanceVariable;
}
};
int classWithStaticVariable::aStaticVariable=1;
int main()
{
classWithStaticVariable t(2);
t.aTestFunctionJustToPrint();
}
Static variable are class variable not instance variable. So these static variable must be initialized with the class definition. Again constructor is used to initialize the instance variable for an object when it is created.Thats all. Thanks
answered Apr 24, 2013 at 10:44
Tunvir Rahman Tusher
6,7102 gold badges39 silver badges33 bronze badges