What is the logic behind size of an empty class = 1? (As per C++)Ex:class base {};main(){printf("Size of the Empty Class is: %dn", sizeof(base));}It gives output: Size of the Empty Class is: 1I have not got the reason / logic behind this.Can anyone help me?

nilesh2080

 Profile Answers by nilesh2080 Questions by nilesh2080

• Mar 11th, 2011

The size of the empty class is i byte because empty class will provide the default constructor, default destructor, default copy constructor and default assigment operator. These function are called by the address of the pointer to functions, so the size of these address is 1 byte.

amitmanish

 Profile Answers by amitmanish Questions by amitmanish

• Mar 4th, 2011

The size of an empty class's object is 1. The reason for this is that suppose if we have the size as 0, then two objects created one after the other would point to the same address. Having the siz...

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Structure: Initially (in C) a structure was used to bundle different type of data types together to perform a particular functionality. But C++ extended the structure to contain functions also. The major difference is that all declarations inside a structure are by default public. Class: Class is a successor of Structure. By default all the members inside the class are private.

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sumitv  

 Profile Answers by sumitv Questions by sumitv

• Member Since Sep-2008 | Sep 4th, 2008

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Structure does support inheritance.

try out the following code.

#include<iostream>

using namespace std;

struct Base
{
    int A;
};

struct Derived:public Base
{
    int B;
    void display();
};

void Derived::display()
{
    cout<<endl<<"A = "<<A<<endl;
}

int main()
{
    Derived D;
    D.A = 111;
    D.display();
    getchar();
    return 0;
}

Try out private and protected inheritance as well. It works. :)

Regards,
Sumit

Sajeed Ullah

• Dec 2nd, 2016

All data members of the class is by default private,
Whereas all data members of structure is by default public.

Ashish

• Mar 24th, 2016

Beware, whatever is supported by a class is also supported by struct whether its inheritance, polymorphism, encapsulation, data hiding etc. etc. as of C++ 11. Only difference is, for a class default access specifier is private whereas for struct its public.

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