CSC161 2010F, Class 08: Input and Output, Continued

Overview:
* Q&A on HW2
* A few notes on HW1
* Review.
* Lab.

Admin:
* You should have received comments on your assignment 1 this morning.  
  Let me know if you did not.
* Are there questions on assignment 2?
* Note that the due date was changed until Thurday.
* I've rearranged the syllabus slightly.  I expected such 
  rearrangements, which is why I included so many "Pause for 
  Breath" days.
* EC for the Kumail performance tonight. 8pm in the Harris High School Gym room
* Read K&R 5.10 (the command line) for Friday.

Questions on Assignment 2

* How do I put more than one thing in the consequent or alternate of an
  if statement?
  * Put brackets around the body of the consequent or alternate and
    put semicolons between the different commands.
* Why might the following code fail to work?

int
main ()
{
  int size = 10;
  int stuff[size];
  stuff[9] = 2;
  return 0;
} // main ()

The fix

#define SIZE 10
int
main ()
{
  int stuff[SIZE];
  stuff[9] = 2;

  ;;; 
  if (wordlen > SIZE)
    {
      ++stuff[SIZE-1];
    }
  else
    {
      ++stuff[wordlen];
    }

  return 0;
} // main ()

A Few Notes on Assignment 1

* Almost no documentation of help.  Did you talk to no one?
* The 'touch' problem
  * Applications are commonly stored in /bin
  * Applications are commonly stored in /usr/bin
  * I can find things with find - slow
  * which touch
  * Why are there two 'touch'es?  Is our system just touch?
    * No, one is a link to the other
* The manual sections

Review
* In C, we typically use scanf to read values and printf to print values.
* Scanf does not work the way we expect.  It does not return the value
  read.  Rather in shoves the value into a variable we provide as a 
  parameter.
* Scanf returns a result: An integer that represents the number of
  variables it filled in.
  scanf ("%d%d%d", &a, &b, &c);
  0 returned: "Agh, I could not read any numbers."
  1 returned: "I read the first number, but not the next two."
  2 returned: I read a and b, but not c
  3 returned: I read a, b, and c
  4 retunred: There has been a break in the space-time continuum
 
* We also did some meta learning: When approaching a new function, one
  should *play* with it.

* We built an amazingly complex program that will soon be the basis of
  a startup.  Our program converts quarts to liters.