Sams Teach Yourself C++ in 21 Days

Answers 867

D

6. The following is one possible answer:
   friend int operator==( const Type& lhs, const Type& rhs );


7. The following is one possible answer:
   0: Exercise 19.7
   1: template
   2: int List::operator==( const Type& lhs, const Type& rhs )
   3: {
   4: // compare lengths first
   5: if ( lhs.theCount != rhs.theCount )
   6: return 0; // lengths differ
   7:
   8: ListCell lh = lhs.head;
   9: ListCell rh = rhs.head;
   10:
   11: for(; lh != 0; lh = lh.next, rh = rh.next )
   12: if ( lh.value != rh.value )
   13: return 0;
   14:
   15: return 1; // if they don’t differ, they must match
   16: }


8. Yes, because comparing the array involves comparing the elements,operator!=
   must be defined for the elements as well.


9. The following is one possible answer:
   0: // Exercise 19.9
   1: // template swap:
   2: // must have assignment and the copy constructor defined for the Type.
   3: template
   4: void swap( Type& lhs, Type& rhs)
   5: {
   6: Type temp( lhs );
   7: lhs = rhs;
   8: rhs = temp;
   9: }

Day 20

Quiz

1. An exception is an object that is created as a result of invoking the keyword throw.
   It is used to signal an exceptional condition, and is passed up the call stack to the
   first catchstatement that handles its type.


2. A tryblock is a set of statements that might generate an exception.

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