Because control names typically are more concise than variable names, using control
names in an expression makes the expression much shorter and easier to understand.
Like the condition in the If"Then"Else statement, the condition in the Do"Loop
statement must evaluate to a Boolean value.
Unlike the variables declared at the beginning of a procedure, variables declared within
a statement block in a selection structure remain in memory until the procedure ends.
You use a problem's solutionin other words, its output, processing, and input