CODEWITHSUNDEEP
c++classinitialization
doge99
doge99

Reputation: 188

What is the difference between class a() and class a = class() in C++?

Coming from the Java and C# world, I always like to use

someclass a = someclass();

instead of

someclass a();

to initalize a class variable in C++. However, my compiler sometimes complain 

Error C2280: Attempting to reference a deleted function

Is there any difference between them? Which one is better?

Upvotes: 5

Views: 1590

Answers (2)

K.Vani
K.Vani

Reputation: 72

Dear Friend in C++ user creates the object as follows

steps

classname objectname;

#include<iostream>
using namespace std;

class demo
{
   public:
      void print()
         {
           cout<<"Demo class";
         }
 };
int main()
   {

      demo d;
      d.print();
      return 0;
   }

OUTPUT Demo class

using pointer object

#include<iostream>
using namespace std;
class demo
{
   public:
      void print()
         {
           cout<<"Demo class using pointer object";
         }
 };

int main()
   {

      demo *d = new demo();
      d->print();
      return 0;
   }

OUTPUT Demo class using pointer object

In java, garbage collection is done automatically. I hope that you understand concept.

Upvotes: -2

O&#39;Neil
O&#39;Neil

Reputation: 3849

Is there any difference between them?

A big one: someclass a(); is declaring a function!

And someclass a = someclass();, before C++17's copy ellision, requires the class to be movable, which is probably not the case here as you get the error Attempting to reference a deleted function.

Which one is better?

None. Use instead:

someclass a;

or

someclass a{}; // C++11

Both will call default constructor.

Upvotes: 9

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