Constructors and Destructors in C++ MCQs with Answers 2027

Q61

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
	A(){
		cout<<"A's Constructor called\n";
	}
};
class B
{
public:
	A a;
	B(){
		cout<<"B's constructor called\ns";
	}
};
int main(int argc, char const *argv[])
{
	B b;
	return 0;
}

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Q62

Open question

What is a copy constructor?

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Q63

Open question

When a copy constructor is called?

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Q64

Open question

Which of the following represents the correct explicit call to a constructor of class A?

class A{
		int a;
	        public:
		A(int i)
                {
			a = i;
		}
       }

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Q65

Open question

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
	~A(){}
};
class B
{
public:
	A a;
};
int main(int argc, char const *argv[])
{
	B b;
	return 0;
}

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Q66

Open question

How many parameters does a default constructor require?

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Q67

Open question

In the following C++ code how many times the string "A's constructor called" will be printed?

#include <iostream>
#include <string>
using namespace std;
class A{
	int a;
public:
	A(){
		cout<<"A's constructor called";
	}
};
class B{
	static A a;
public:
	B(){
		cout<<"B's constructor called";
	}
	static A get(){
		return a;
	}
};
A B::a;
int main(int argc, char const *argv[])
{
	B b;
	A a1 = b.get();
	A a2 = b.get();
	A a3 = b.get();
}

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Q68

Open question

What is the role of destructors in Classes?

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Q69

Open question

What is syntax of defining a destructor of class A?

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Q70

Open question

What happens if a user forgets to define a constructor inside a class?

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Q71

Open question

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
public:
	int a;
};
int main(int argc, char const *argv[])
{
	A a1 = {10};
	A a2 = a1;
	cout<<a1.a<<a2.a;
	return 0;
}

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Q72

Open question

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
public:
	int a;
	A(){
		cout<<"Constructor called\n";
	}
} a;
int main(int argc, char const *argv[])
{
	cout<<"Main function\n";
	return 0;
}

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Q73

Open question

What will be the output of the following C++ code?

#include <iostream>
#include <string>
using namespace std;
class A{
	int a;
	A(){
		a = 5;
	}
 
public:
	void assign(int i){
		a = i;
	}
	int return_value(){
		return a;
	}
};
int main(int argc, char const *argv[])
{
	A obj;
	obj.assign(10);
	cout<<obj.return_value();
}

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Q74

Open question

What will be the output of the following C++ code?

#include <iostream>
#include <string>
using namespace std;
class A{
	mutable int a;
public:
	A(){
		cout<<"A's Constructor called\n";
	}
	~A(){
		cout<<"A's Destructor called\n";
	}
};
class B: public A{
	A a;
public:
	B(){
		cout<<"B's Constructor called\n";
	}
	~B(){
		cout<<"B's Destructor called\n";
	}
};
int main(int argc, char const *argv[])
{
	B b1;
}

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Q75

Open question

What will be the output of the following C++ code?

#include <iostream>  
using namespace std;
class A{
	A(){
		cout<<"A's Constructor called\n";
	}
	friend class B;
};
class B
{
public:
	A a;
	B(){
		cout<"B's constructor called\ns";
	}
};
int main(int argc, char const *argv[])
{
	B b;
	return 0;
}

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Q76

Open question

What is the role of a constructor in classes?

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Q77

Open question

How many Destructors are allowed in a Class?

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Constructors and Destructors in C++practice.

Constructors and Destructors in C++
practice.