Exceptions Classes And Inheritance

Exceptions and member functions

• Exceptions are useful in member functions.

Example: Overloaded [] operator. However, value nIndex should be a valid array index and this is not checked.

int IntArray::operator[](const int nIndex)
{
    return m_nData[nIndex];
}

With the use of an exception: Now, if the user passes in an invalid exception, operator[] will throw an int exception.

int IntArray::operator[](const int nIndex)
{
    if (nIndex < 0 || nIndex >= GetLength())
        throw nIndex;
 
    return m_nData[nIndex];
}

Constructors

• When constructors fail, it cannot return a value.
• You could simply throw an exception to indicate the object failed to create.

Exception class

• An exception class is just a normal class that is designed specifically to be thrown as an exception.