LOOPS:
  What is the EXACT output of the following code?

  for ( int i = 0 ; i < 10 ; i += 2 ) {
    cout << i << endl;
  }

  for ( int count = 10 ; count >= 0 ; count-- ) {
    cout << count << ' ';
  }
  cout << endl;

  for ( int j = 20 ; j >= 0 ; j -= 3 ) {
    cout << j << "..";
  }
  cout << endl;

  for ( int k = 1 ; k != 6 ; k += 2 ) {
    cout << k << ' ';
  }
  cout << endl;


  Write a for loop to count from 10 to 1000 by 10s.

 
 ANSWERS:
 0
 2
 4
 6
 8

 10 9 8 7 6 5 4 3 2 1 0

 20..17..14..11..8..5..2..

 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 ... !!!

  // count from 10 to 1000 by 10s
  for ( int i = 10 ; i <= 1000 ; i += 10 ) {
    // ... loop body
  }


 A for loop is used to count when we know
  both endpoints (e.g. count from 1 to 10000)

 A while loop is used when we don't know how
  many times we'll iterate through the loop



 Write a program to ask the user how many grades
  they want to type in.  Then loop that many times
  (using a for loop) and ask for each grade value.
 Calculate the average.


 Next, write the same program, but use a while loop
  and don't ask the user how many grades to enter.
 Keep looping until the user inputs -1 (which is
  a "sentinel value")
 Show the average grade (make sure you don't
  include -1 in the calculations...)



 WHAT IS THE OUTPUT OF THIS NESTED LOOP?

 for ( int j = 0 ; j <= 10 ; j += 5 ) {
   for ( int k = 10 ; k > 0 ; k -= 5 ) {
     cout << j << " and " << k << endl;
   }
 }