CSC 180
Notes for Tutorial #2
To be given week of 23rd September

Monday 23 Sept  

Wednesday 25 Sept  

============ Notes for the tutorial ============================================


 AN ALGORITHM FOR COMPUTING FIBONACCI SEQUENCES
===============================================


Problem
=======

The following sequence of numbers, called the Fibonacci sequence,
  1 1 2 3 5 8, 13, 21, ...
has the property that each term after the first two terms is the sum
of the two proceeding terms.   Develop an algorithm to generate the first
50 terms of this sequence.

Solution
========

Work them towards something like:

  termA = 1
  print termA
  termB = 1
  print termB
  set i to 2
  repeat as long as i < 50      ( <-- mention that 50 is a "constant" )
      i = i + 1
      termC = termA + termB
      print termC
      termA = termB 
      termB = termC 
  end repeat

Try to work with their suggestions - and if they are wrong, try to
get them to figure out what is wrong with their ideas.

Motivate: the use of counters in a loop, the fact that we don't need to
store all of the computed terms in their own variables  - only the two
needed for the next calculation, how we need to update the variables at 
the bottom of the loop in preparation for the next iteration.

Get them to figure out the termination conditions for the repetition.
Point out that in the repetition, some of the statements are "for the current
iteration" in the repetition and some of the statements "prepare for the
next iteration."

Please perform a trace of the algorithm that you develop.  I haven't done
tracing yet in class, so go very slowly for at least 3 iteration so
that they can see the "flow" through the variables i, termA, termB and
termC.


 Using formats with scanf and printf
====================================
 
Problem
=======

Write a program that formats product information entered by the 
user.  A session with the program shoud look like this:

Enter item number: 583 <Enter>
Enter unit price: 13.5 <Enter>
Enter purchase date (mm/dd/yy): 10/24/95

Item		Unit		Purchase 
        	Price           Date

583		$  13.50	10/24/95

(The item number and date should be left justified; the unit price
should be right justified.  Allow dollar amounts up to $9999.99.
Hint: Use tabs to line up the columns.)

A solution
==========

/* Program to demonstrate the use of formats for Input/Output. */
int main()
{
    int  itemNumber;
    double unitPrice;
    int  month, day, year;  /* the purchase date */

    /* Prompt for and get the item number. */
    printf("Enter item number: ");
    scanf("%d",&itemNumber);

    /* Prompt for and get the unit price. */
    printf("Enter unit price: ");
    scanf("%lg",&unitPrice);

    /* Prompt for and get the purchase date . */
    printf("Enter purchase date (mm/dd/yy): ");
    scanf("%d/%d/%d",&month,&day,&year);

    /* Print out the given information in a formatted table. */
    printf("Item\t\tUnit \t\tPurchase \n");
    printf("    \t\tPrice\t\tDate     \n");
    printf("%-d \t\t$%7.2f\t%2d/%2d/%2d\n", 
           itemNumber, unitPrice, month, day, year);

    return 0;
}