Last Updated : 23 Jul, 2025
Copy constructor and Assignment operator are similar as they are both used to initialize one object using another object. But, there are some basic differences between them:
Copy constructor Assignment operator It is called when a new object is created from an existing object, as a copy of the existing object This operator is called when an already initialized object is assigned a new value from another existing object. It creates a separate memory block for the new object. It does not automatically create a separate memory block or new memory space. However, if the class involves dynamic memory management, the assignment operator must first release the existing memory on the left-hand side and then allocate new memory as needed to copy the data from the right-hand side. It is an overloaded constructor. It is a bitwise operator. C++ compiler implicitly provides a copy constructor, if no copy constructor is defined in the class. A bitwise copy gets created, if the Assignment operator is not overloaded.Syntax:
className(const className &obj) {
// body
}
Syntax:
className obj1, obj2;
obj2 = obj1;
Consider the following C++ program.
CPP
// CPP Program to demonstrate the use of copy constructor
// and assignment operator
#include <iostream>
#include <stdio.h>
using namespace std;
class Test {
public:
Test() {}
Test(const Test& t)
{
cout << "Copy constructor called " << endl;
}
Test& operator=(const Test& t)
{
cout << "Assignment operator called " << endl;
return *this;
}
};
// Driver code
int main()
{
Test t1, t2;
t2 = t1;
Test t3 = t1;
getchar();
return 0;
}
Assignment operator called Copy constructor called
Explanation: Here, t2 = t1; calls the assignment operator, same as t2.operator=(t1); and Test t3 = t1; calls the copy constructor, same as Test t3(t1);
Must Read: When is a Copy Constructor Called in C++?
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