C++ References

Question 1

Which of the following functions must use reference.

• Assignment operator function
• Copy Constructor
• Destructor
• Parameterized constructor

Question 2

What is the return value of f(p, p) if the value of p is initialized to 5 before the call? Note that the first parameter is passed by reference, whereas the second parameter is passed by value.

int f(int &x, int c) {
   c  = c - 1;
   if (c == 0) return 1;
   x = x + 1;
   return f(x, c) * x;
} 

• 3024
• 6561
• 55440
• 161051

Question 3

Which of the following is FALSE about references in C++

• References cannot be NULL
• A reference must be initialized when declared
• Once a reference is created, it cannot be later made to reference another object; it cannot be reset.
• References cannot refer to constant value

Question 4

Predict the output of following C++ program.

C

#include<iostream>
using namespace std;

int &fun()
{
    static int x = 10;
    return x;
}
int main()
{
    fun() = 30;
    cout << fun();
    return 0;
}

• Compiler Error: Function cannot be used as lvalue
• 10
• 30

Question 5

CPP

#include<iostream>
using namespace std;

int &fun()
{
    int x = 10;
    return x;
}
int main()
{
    fun() = 30;
    cout << fun();
    return 0;
}

• May cause runtime error
• May cause compiler error
• Always works fine.
• 0

Question 6

Output of following C++ program?

CPP

#include<iostream>
using namespace std;

int main()
{
  int x = 10;
  int& ref = x;
  ref = 20;
  cout << \"x = \" << x << endl ;
  x = 30;
  cout << \"ref = \" << ref << endl;
  return 0;
}

• x = 20
  ref = 30
  

• x = 20
  ref = 20
  

• x = 10
  ref = 30
  

• x = 30
  ref = 30