C++ Copying vs Assignment Copy Constructor Vs Assignment Constructor
Example
Ok we have briefly looked over what the copy constructor and assignment constructor are above and gave examples of each now let's see both of them in the same code. This code will be similar as above two. Let's take this :
// Copy vs Assignment Constructor
#include <iostream>
#include <string>
using std::cout;
using std::endl;
class Foo
{
public:
Foo(int data)
{
this->data = data;
}
~Foo(){};
Foo(const Foo& rhs)
{
data = rhs.data;
}
Foo& operator=(const Foo& rhs)
{
data = rhs.data;
return *this;
}
int data;
};
int main()
{
Foo foo(2); //Foo(int data) / Normal Constructor called
Foo foo2 = foo; //Copy Constructor Called
cout << foo2.data << endl;
Foo foo3(42);
foo3=foo; //Assignment Constructor Called
cout << foo3.data << endl;
}
Output:
2
2
Here you can see we first call the copy constructor by executing the line Foo foo2 = foo; . Since we didn't initialize it previously. And then next we call the assignment operator on foo3 since it was already initialized foo3=foo;
