Algorithm for numbers divisible by 9 not 6

Assumptions: numbers are read as text so that the word NO can be detected; at least 50 numbers must be entered before NO is accepted; a number qualifies if it is between 1 and 100, divisible by 9 and not divisible by 6 (these are 9, 27, 45, 63, 81, 99).

Variables: total (numbers read), count (qualifying numbers), sum.

Algorithm

1. Start
2. Set total = 0, count = 0, sum = 0
3. Read input
4. If input = NO: if total >= 50 go to step 8, otherwise print "Enter at least 50 numbers" and go to step 3
5. Convert input to the integer n and set total = total + 1
6. If n >= 1 and n <= 100 and n mod 9 = 0 and n mod 6 != 0, then set sum = sum + n and count = count + 1
7. Go to step 3
8. If count = 0, print "No such number was entered"
9. Otherwise calculate avg = sum / count and print sum and avg
10. Stop

Flowchart

Part 1: reading and testing the numbers

        ( Start )
            |
  [ total=0, count=0, sum=0 ]
            |
     +----->|<-----------------+ (B)
     |      v                   |
     | / Read input /           |
     |      |                   |
     | < input = NO ? >--Yes--> (A)
     |      | No
     | [ n = integer(input) ]
     | [ total = total + 1 ]
     |      |
     | < n>=1, n<=100, n%9=0, n%6!=0 ? >
     |    No |            | Yes
     |       |    [ sum = sum + n ]
     |       |    [ count = count + 1 ]
     +-------+------------+

Part 2: after NO is entered

    (A)
     |
 < total >= 50 ? >--No--> / Print "Enter at least 50" /
     | Yes                          |
     |                             (B) back to Read input
 < count = 0 ? >--Yes--> / Print "No such number" /
     | No                           |
 [ avg = sum / count ]              |
 / Print sum, avg /                 |
     |                              |
     +-------------+----------------+
                   |
               ( Stop )

Example: if the qualifying numbers entered are 9, 27 and 45, then sum = 81, count = 3 and average = 27.