WB JECA MCA Object Oriented Programming OOPs Previous Year Questions (PYQs)
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Find the output from the following C++ code snippet:
class A
{
public: void show()
{
cout<<"Class A
";
}
};
class B: public A
{
public: void show()
{
A::show();
cout<<"Class B";
}
};
int main()
{
B obj;
obj.show();
}
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Solution
Calls A::show then prints Class B.
What will be the output of this program? class Test { public: static int x; Test() { x++; } void display() { cout<
#include
using namespace std;
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Solution
x=5 → t1→6, t2→7.
How many parameters does a default constructor require ?
(A) 1
(B) 2
(C) 0
(D) 3
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Solution
- A default constructor in C++ is a constructor that takes no arguments.
- It is invoked automatically when an object is created without passing parameters.
Correct Answer: (C) 0
What is the output of the following C++ code? class Base { public: virtual void show() { cout<<"Base"; } }; class Derived: public Base { public: void show() override{ cout<<"Derived"; } }; int main() { Base* ptr; Derived d; ptr=&d; ptr->show(); return 0; }
#include
using namespace std;
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Solution
Virtual function → Derived called.
The keyword friend does not appear in
(A) the class allowing access to another class.
(B) the class desiring access to another class.
(C) the private section of a class.
(D) the public section of a class.
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Solution
- The
friendkeyword is used inside a class definition to allow another class or function to access its private/protected members. - It appears in the class granting access (not the one desiring access).
- It can be declared in either public or private section of that class.
Correct Answer: (B) the class desiring access to another class
Which among the following can’t be used for polymorphism?
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Solution
Solution: Static member functions cannot be virtual; hence they don’t participate in runtime polymorphism.
Overloading (functions/operators/constructors) supports polymorphism.
Answer: (A) Static member functions
Answer: (A) Static member functions
If a file has read and write permission for the owner, then the octal representation of the permissions will be:
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Solution
Solution: Read=4, Write=2 ⇒ total = 6.
Answer: (C) 6
Answer: (C) 6
Identify the incorrect constructor type:
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Solution
Solution: In C++, there is no concept of Friend Constructor. Others exist.
Answer: (A) Friend Constructor
Answer: (A) Friend Constructor
Making class members inaccessible to nonmember functions is an example of:
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Solution
Solution: Restricting access to internal details of a class is data hiding (encapsulation).
Answer: (B) data hiding
Answer: (B) data hiding
Which is the correct statement about operator overloading ?
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Solution
Solution: Overloading changes operator meaning for user types, but its precedence and associativity never change.
Answer: (D)
Answer: (D)
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and More.
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