1. GCSE Computing:: While Loops

2. While Loops: Why we need them
While loops will repeat something until the user does something that the program allows;
The following would be good reasons for using a While Loop:
You want to stop the user from entering a value below 0
For example when pricing items;
You want to do something until the time runs out
For example you want to keep a count of the number of customers entering your shop until closing time;
You want to continue running your program until there is an error
For example you want to keep printing until the ink runs out

3. While Loops: In practice
The following code asks the user to enter their name, if no name is entered then it will keep requesting until something is entered:
Dim sName
sName = Inputbox (“Please enter your name”)
While sName = “”
Wend
The following code will run the procedure count_customers continuously until the shop closes:
Dim tTime
tTime = Now()
While tTime < “17:00”
count_customers()