More Exceptional C++

Chapter 9. Equivalent Code?

Difficulty: 5

Can subtle code differences really matter, especially in something as simple as postincrementing a function parameter? This Item explores an interesting interaction that becomes important in STL-style code.

1. Describe what the following code does:

   // Example 9-1
   //
   f( a++ );
   

   Be as complete as you can about all possibilities.

2. What is the difference, if any, between the following two code fragments?

   // Example 9-2(a)
   //
   f( a++ );
   
   // Example 9-2(b)
   //
   f( a );
   a++;
   

3. In Question #2, make the simplifying assumption that f() is a function that takes its argument by value, and that a is an object of class type that has an operator++(int) with natural semantics. Now what is the difference, if any, between Example 9-2(a) ...