Classes and Objects in C++ MCQ question and answer with solution | C++ Programimg MCQs

#include <iostream>
#include <string>
using namespace std;
class Box
{
	int capacity;
    public:
	Box(int cap){
		capacity = cap;
	}
	friend void show();
};
 
void Box::show()
{	
	Box b(10);
	cout<<"Value of capacity is: "<<b.capacity<<endl;
}
 
int main(int argc, char const *argv[])
{
	show();
	return 0;
}

#include <iostream>
#include <string>
using namespace std;
int main ()
{
    string str ("steve jobs is legend");
    string::iterator it;
    str.erase (str.begin()+ 5, str.end()-7);
    cout << str << endl;      
    return 0;
}

#include <iostream> 
using namespace std;
class A
{
    public:
    int x;
    A(int n = 0) : x(n) {};
    int& operator[](int n)
    {
         cout << "0" ;
         return x;
    }
    int operator[](int n) const
    {
         cout << "1" ;
         return x;
    }
 };
void foo(const A& a)
{
    int z = a[2];
}
int main()
{
    A a(7);
    a[3]  = 8;
    int z = a[2];
    foo(a);
    return 0;
}

#include <iostream>
using namespace std;
class Box
{
    double width;
    public:
    friend void printWidth( Box box );
    void setWidth( double wid );
};
void Box::setWidth( double wid )
{
    width = wid;
}
void printWidth( Box box )
{
    box.width = box.width * 2;
    cout << "Width of box : " << box.width << endl;
}
int main( )
{
    Box box;
    box.setWidth(10.0);
    printWidth( box );
    return 0;
}

#include <iostream>
using namespace std;
class Complex
{
    private:
    float real;
    float imag;
    public:
    Complex():real(0), imag(0){}
    Complex operator ()(float re, float im)
    {
        real += re;
        imag += im;
        return *this;
    }
    Complex operator() (float re)
    {
        real += re;
        return *this;
    }
    void display()
    {
        cout << "(" << real << "," << imag << ")" << endl;
    }
};
int main()
{
    Complex c1, c2;
    c2 = c1(3.2, 5.3);
    c1(6.5, 2.7);
    c2(1.9);
    cout << "c2=";c1.display();
    cout << "c2=";c2.display();
    return 0;
}

#include <iostream>
#include <complex>
using namespace std;
int main()
{
    complex<double> c1(4.0, 3.0);
    complex<float> c2(polar(5.0, 0.75));
    cout  << (c1 += sqrt(c1)) << endl;
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
class Box
{
    int capacity;
    Box(){}
    Box(double capacity){
        this->capacity = capacity;
    }
};
int main(int argc, char const *argv[])
{
    Box b1(10);
    Box b2 = Box(14);
    return 0;
}

#include <iostream>
#include <string>
using namespace std;
class B
{
	int b;
   public:
	B(){}
	B(int i){
		b = i;
	}
	int show(){
		return b;
	}
};
 
class C
{
	B b;
    public:
	C(int i){
		b = B(i);
	}
	friend void show(){
 
		C c(10);
		cout<<"value of b is: "<<c.b.show()<<endl;
	}
};
 
int main(int argc, char const *argv[])
{
	show();
	return 0;
}

#include <iostream>
#include <string>
using namespace std;
class Box{
    int capacity;
public:
    Box(){}
    Box(double capacity){
	this->capacity = capacity;
    }
};
int main(int argc, char const *argv[])
{
    Box b1(10);
    Box b2 = Box(14);
    if(b1 == b2){
	cout<<"Equal";
    }
    else{
        cout<<"Not Equal";
    }
    return 0;
}