CMPS 222 - Lab 8

Lab 8 - Exception Handling

The purpose of this lab is to add exception handling to the DoubleList class used in Lab 5. We will use the basic exception handling syntax we learned at the end of lecture on Wednesday.

Copy the fixed implementation file from list_fixed.cpp to a file called lab8.cpp. In lab8.cpp, you are going to an exception-based index operator. This MUST be an index operator that returns a double reference so we can use the index operator to update the list's contents.

First, add an empty exception class above the DoubleList class definition:

InvalidIndex - An empty exception class that will indicate that the index given to the index operator is not valid for this array.

Next, add the index operator. In the body of the index operator function, if the given index is less than 0 or greater than size - 1, throw an InvalidIndex exception and do NOT print anything out (main() will handle printing out an error message now). Otherwise, return the requested element.

Finally, update your main() function to implement the following pseudocode:

allocate a DoubleList with 10 elements (constructor that takes an array and integer)
for each element in the list
  prompt the user for element i
  read in element i
end-for
do
  ask the user for an index they wish to access in the list
  read the user's response into index
  set flag to true
  try
    print out the requested index
  catch InvalidIndex
    output that the index is bad
    set flag to false
while flag is false

This main() function will let you test that you have done the InvalidIndex exception correctly. It should keep asking for a new index until you give an index between 0 and 9.

Email your completed lab8.cpp to me.