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C++ Operator Overloading

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Question 1

How can we restrict dynamic allocation of objects of a class using new?

By overloading new operator
By making an empty private new operator.
By making an empty private new and new[] operators
By overloading new operator and new[] operators

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Question 2

Which of the following operators are overloaded by default by the compiler in every user defined classes even if user has not written?

1) Comparison Operator ( == )
2) Assignment Operator ( = )

Both 1 and 2
Only 1
Only 2
None of the two

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Question 3

Which of the following operators should be preferred to overload as a global function rather than a member method?

Postfix ++
Comparison Operator
Insertion Operator <<
Prefix++

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Question 4

How does C++ compiler differs between overloaded postfix and prefix operators?

C++ doesn\'t allow both operators to be overloaded in a class
A postfix ++ has a dummy parameter
A prefix ++ has a dummy parameter
By making prefix ++ as a global function and postfix as a member function.

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Question 5

Predict the output?

CPP

#include<stdlib.h>
#include<stdio.h>
#include<iostream>

using namespace std;

class Test {
    int x;
public:
    void* operator new(size_t size);
    void operator delete(void*);
    Test(int i) {
        x = i;
        cout << "Constructor called \\n";
    }
    ~Test() { cout << "Destructor called \\n"; }
};


void* Test::operator new(size_t size)
{
    void *storage = malloc(size);
    cout << "new called \\n";
    return storage;
}

void Test::operator delete(void *p )
{
    cout<<"delete called \\n";
    free(p);
}

int main()
{
    Test *m = new Test(5);
    delete m;
    return 0;
}

new called
Constructor called
delete called
Destructor called

new called
Constructor called
Destructor called
delete called

Constructor called
new called
Destructor called
delete called

Constructor called
new called
delete called
Destructor called

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Question 6

CPP

#include<iostream>
using namespace std;

class Point {
private:
  int x, y;
public:
  Point() : x(0), y(0) { }
  Point& operator()(int dx, int dy);
  void show() {cout << "x = " << x << ", y = " << y; }
};

Point& Point::operator()(int dx, int dy)
{
    x = dx;
    y = dy;
    return *this;
}

int main()
{
  Point pt;
  pt(3, 2);
  pt.show();
  return 0;
}

x = 3, y = 2
Compiler Error
x = 2, y = 3

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Question 7

Which of the following operator(s) cannot be overloaded?

. (Member Access or Dot operator)
?: (Ternary or Conditional Operator )
:: (Scope Resolution Operator)
All of the above

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Question 8

Which of the following operator functions cannot be global, i.e., must be a member function.

new
delete
Converstion Operator
All of the above

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Question 9

Output of following program?

#include <iostream>
using namespace std;
class Test2
{
    int y;
};

class Test
{
    int x;
    Test2 t2;
public:
    operator Test2 ()  { return t2; }
    operator int () { return x; }
};

void fun ( int x) { cout << "fun(int) called"; }
void fun ( Test2 t ) { cout << "fun(Test 2) called"; }

int main()
{
    Test t;
    fun(t);
    return 0;
}

fun(int) called
fun(Test 2) called
Compiler Error: Ambiguous call to fun()

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Question 10

Predict the output

CPP

#include<iostream>
using namespace std;
class A
{
    int i;
public:
    A(int ii = 0) : i(ii) {}
    void show() {  cout << i << endl;  }
};

class B
{
    int x;
public:
    B(int xx) : x(xx) {}
    operator A() const {  return A(x); }
};

void g(A a)
{
    a.show();
}

int main()
{
    B b(10);
    g(b);
    g(20);
    return 0;
}

Compiler Error
```
10
20
```
```
20
20
```
```
10
10
```

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