Class 33: Reading Lines (1)

Held: Monday, 31 March 2003

Overview:

• General exam 1 issues.
• Some string notes.
• Implementing readLine.

Related Pages:

• EBoard.
• Notes on exam 1.
• readLine.h.

Notes:

• While grading exam 1, I noted some significant problems. I expect that some of the problems had to do with time pressures. I also expect that we were moving a little too fast for some of you. We're going to spend much of this week (except for Gries Tuesday) working on exam problems together. See the notes on this exam for more details.
• Would the class like to meet in Saints Rest some time next week or the week after? I'll spring for coffee and rolls. (I'll need to look at topics to decide on a day.)

General

• Do not put in error messages in the middle of utility functions.
• Include full cites.
• > See the notes on the exam for detailed notes on stylistic issues.

Some String Errors

• What's wrong with the following test for strncpy?

  main()
  {
    char *result;
    strncpy(result, "hello" 6);
    ...
  } /* main() */
  

• What's wrong with this test?

  main()
  {
    char *result;
    strncpy(result, "hello" 6);
    ...
  } /* main() */
  

Writing readLine

Preconditions and Postconditions

• Let's spend the time carefully specifying preconditions and postconditions.

Testing

*> Rather than starting with the design of readLine, we'll start by thinking about how we might design a test program for it.

• Consideration one: What are special cases we should worry about?
• Consideration two: Interactive or non-interactive? (Or somewhere in between?) *> Consideration three: How should we specify string length? *> We'll put it together together.