1. Indicate data flow on the main algorithm. Evidence – Algorithm with data flow. (3)

Remember the purpose of data flow is to let you see what variables pass information  between sub programs. This also allows us to see the required variables and determine if they are ByRef or ByVal. So don’t skip this step and try to bluff it later, 5 minutes now will save you 30 at the computer. It’s also worth remembering that input and output within the program is not the same as input and output from the program, so we don’t care about what the user types in.

The guidelines for teachers says – To be awarded the marks for data flow it is necessary for candidates to display the data flow in their top-level design (main algorithm).

1. Fire up the word processor and write in the main algorithm “as is”, don’t use a number list, just type it in and don’t forget about the indentation.
2. Spend some time looking at the test data and sample outputs. Read back over the task description, are there any clues about what data goes in and out of the sections?
3. Edit the main algorithm to give yourself a couple of lines between each step (now it makes sense as to why you were not to use a number list)
4. Add the outputs for step 1, give some thought to the names of the variables, you are going to be working with them fora  while, so make sure they are not too long but do describe what they store. ( I have left the formatting on for the screen shot so you can see tabs for indentation etc.)
5. Algorithm step 2 does not require any information from step 1 so we can just go ahead and fill in theutputs. Do we require the forename and surname or just the generated customer code? Look at the sample output to make up your mind.
6. Remember we only require data flow for sub programs so algorithm step 3, 8 and 10 do not require data flow.
7. The data flow for step 4 is all output as well, although it doesn’t say it a validated output here would save you a lot of problems later in the code.
8. Step 5,6 & 7 require the outputs from step 1 as inputs but do they have any outputs?
9. Finally step 9 requires some info. from step 2
10. Remove any unused INPUT/OUTPUT statements and check over it for mistakes before printing it out.