what is object slicing in c++?

[Madaleno]

Hi,
I am F.Y.B.Sc.IT student. I Recently started learning C++ language which is in our syllabus. In our last tutorial there was one question what is object slicing in c++? I tried to find out answer of this question in C++ book but I unable to find answer. So I decided to get help of you. If you know anything about this question please share with me.
Thank you.

[Praetor]

When your child class object is manually assigned to parent class, the parent class's contents in the child class object are copied to the parent class leaving behind the child class specific contents. This mechanism is referred as Object Slicing.

Class Parent
{
public:
  int p;
};

class Child : public Parent
{
public:
  int q;
};

int main()
{
  Parent Bj;
  Child Dj;
  Bj = Dj;  //Here Dj contains both p and q. 
               //But only p is copied to Bj.
}

[Katty]

When an parent class is assigned to its child class, the parent class takes up only the parent member data leaving the data members of child class.This process is called as object slicing.

[kelfro]

If an object of a child class is assigned to a parent class object,the compiler accepts only the parent portion of the object.

class parent
{
   public:
           int p,q;
};
class child : public parent
{
  private:
          int t;
};
int main()
{
   parent x;
   child y;
   x=y;
return o;
}

[Zecho]

From this program you can get idea of object slicing

class parent 
{
 public int p,q;
}
class child extends parent
{
public int t;
}
class main
{
public static void main(String[] s)
{
parent x = new parent();
drived y  = new child();
x.p=10;
x.q=20;
System.out.println("this is class parent p=10,q=20");
System.out.println("p =" +x.p);
System.out.println("j =" +x.q);
System.out.println("this is class child p=100,q=200,t=300");
y.=100;
y.j=200;
y.k=300;
System.out.println("p =" +y.p);
System.out.println("q =" +y.q);
System.out.println("t =" +y.t);
x=y;

System.out.println("after the assignment");
System.out.println("p =" +x.p);
System.out.println("q =" +x.q);
//System.out.println("t =" +x.t);
System.out.println("now you know what is object slicing");
}
}

[Reegan]

Object slicing happened when we assign an instance of the
child class to a variable of type parent class.

class Parent
{
    int avariable;
};
 
class Child : public Parent
{
    int bvariable;
};
 
Child x;
Parent y = x; 
 
Child x2;
Parent &y = x2;
y = x;