What is the difference between these object instantiation methods?

What is the difference between these object instantiation methods:

1.

Code:

---

ClassName ObjectName;

---

2.

Code:

---

ClassName ObjectName();

---

Is there any?

The latter declares a function that takes no arguments and returns a ClassName.

Quote:

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Originally Posted by Feoggou

What is the difference between these object instantiation methods:

---

There is no instantiation going on in the second method. That's a function declaration.

See here:

Code:

---

#include <string>

int main()

struct ClassName
{
};

ClassName ObjectName();  // declare function

int main()
{
    ClassName theName;
    theName = ObjectName();
}


// here is the function impelemtation
ClassName ObjectName()
{
  return ClassName();
}

---

See the code in red?

Regards,

Paul McKenzie

http://www.parashift.com/c++-faq-lit....html#faq-10.2

thanks a lot.

It seems that if you have a class defined like this:

Code:

---

class ClassName
{
    int x;
public:
    ClassName()
  {
      x = 3;
  }
};

---

you can use either this:

Code:

---

ClassName obj;

---

or this:

Code:

---

ClassName obj();

---

And I was saying to myself: there can't be any difference!