MCQ On Exception Handling in C++: Multiple Choice Questions and Answers on C++ Exception Handling

Output of following program

#include<iostream>
using namespace std;
 
class Base {};
class Derived: public Base {};
int main()
{
   Derived d;
   try {
       throw d;
   }
   catch(Base b) {
        cout<<"Caught Base Exception";
   }
   catch(Derived d) {
        cout<<"Caught Derived Exception";
   }
   return 0;
}

What should be put in a try block?

1. Statements that might cause exceptions
2. Statements that should be skipped in case of an exception

What happens in C++ when an exception is thrown and not caught anywhere like following program.

#include <iostream>
using namespace std;
 
int fun() throw (int)
{
    throw 10;
}
 
int main() {
 
  fun();
 
  return 0;
}

#include <iostream>
using namespace std;
 
class Test {
  static int count;
  int id;
public:
  Test() {
    count++;
    id = count;
    cout << "Constructing object number " << id << endl;
    if(id == 4)
       throw 4;
  }
  ~Test() { cout << "Destructing object number " << id << endl; }
};
 
int Test::count = 0;
 
int main() {
  try {
    Test array[5];
  } catch(int i) {
    cout << "Caught " << i << endl;
  }
}

1. 

Constructing object number 1
Constructing object number 2
Constructing object number 3
Constructing object number 4
Destructing object number 1
Destructing object number 2
Destructing object number 3
Destructing object number 4
Caught 4

2.

Constructing object number 1
Constructing object number 2
Constructing object number 3
Constructing object number 4
Destructing object number 3
Destructing object number 2
Destructing object number 1
Caught 4

3. 

Constructing object number 1
Constructing object number 2
Constructing object number 3
Constructing object number 4
Destructing object number 4
Destructing object number 3
Destructing object number 2
Destructing object number 1
Caught 4

4. 

Constructing object number 1
Constructing object number 2
Constructing object number 3
Constructing object number 4
Destructing object number 1
Destructing object number 2
Destructing object number 3
Caught 4

#include <iostream>
using namespace std;
 
class Test {
public:
   Test() { cout << "Constructing an object of Test " << endl; }
  ~Test() { cout << "Destructing an object of Test "  << endl; }
};
 
int main() {
  try {
    Test t1;
    throw 10;
  } catch(int i) {
    cout << "Caught " << i << endl;
  }
}

1. 

Caught 10

2.

Constructing an object of Test 
Caught 10

3. 

Constructing an object of Test 
Destructing an object of Test 
Caught 10

4. 

Compiler Errror

What is the advantage of exception handling ?

1. Remove error-handling code from the software's main line of code.
2. A method writer can chose to handle certain exceptions and delegate others to the caller.
3. An exception that occurs in a function can be handled anywhere in the function call stack

#include <iostream>
using namespace std;
 
int main()
{
    try
    {
       throw 'a';
    }
    catch (int param)
    {
        cout << "int exceptionn";
    }
    catch (...)
    {
        cout << "default exceptionn";
    }
    cout << "After Exception";
    return 0;
}

1. 

default exception
After Exception

2. 

int exception
After Exception

3. 

int exception

4. 

default exception

#include <iostream>
using namespace std;
int main()
{
   int x = -1;
   try {
      cout << "Inside try n";
      if (x < 0)
      {
         throw x;
         cout << "After throw n";
      }
   }
   catch (int x ) {
      cout << "Exception Caught n";
   }
 
   cout << "After catch n";
   return 0;
}

1.

Inside try
Exception Caught
After throw 
After catch

2. 

Inside try
Exception Caught
After catch

3. 

Inside try
Exception Caught

4. 

Inside try
After throw
After catch

#include <iostream>
using namespace std;
 
int main()
{
    try
    {
       throw 10;
    }
    catch (...)
    {
        cout << "default exceptionn";
    }
    catch (int param)
    {
        cout << "int exceptionn";
    }
 
    return 0;
}

#include <iostream>
using namespace std;
 
int main()
{
    try
    {
        try
        {
            throw 20;
        }
        catch (int n)
        {
            cout << "Inner Catchn";
            throw;
        }
    }
    catch (int x)
    {
        cout << "Outer Catchn";
    }
    return 0;
}

1.

Outer Catch

2.

Inner Catch

3.

Inner Catch
Outer Catch

4.

Compiler Error

Which of the following is true about exception handling in C++? 1) There is a standard exception class like Exception class in Java. 2) All exceptions are unchecked in C++, i.e., compiler doesn't check if the exceptions are caught or not. 3) In C++, a function can specify the list of exceptions that it can throw using comma separated list like following.

void fun(int a, char b) throw (Exception1, Exception2, ..) 

What happens when a function throws an error but doesn't specify it in the list of exceptions it can throw. For example, what is the output of following program?

#include <iostream>
using namespace std;
 
// Ideally it should have been "int fun() (int)"
int fun()
{
    throw 10;
}
 
int main()
{
    try
    {
        fun();
    }
    catch (int )
    {
        cout << "Caught";
    }
    return 0;
}