Last week, Madam Sharin Hazlin had told us to post new entry about what are the difference between these two repetition structure
DO......... UNTIL AND DO.......WHILE?
Repetition Structure : When we talk about allows a user to specify that a program should repeat an action while some condition remains true.
DO..... UNTIL (DOU)
The DOU operations allow the processing of a group of calculations one or more times. The end of a Do-Until operation is indicated by an ENDDO operation. Here processing is done at least one time.
DO...... WHILE (DOW)
The DOW operations allow the processing of a group of calculations zero or more times. The end of a Do-While operation is indicated by an ENDDO operation.
The do-while is very similar to the regular while with just one difference. The while is a leading decision loop, but the do-while is a trailing decision loop. Therefore the condition is at the beginning of the while loop but at the end of the do-while loop. For that reason a while may be executed zero times, such as when the condition is initially false. On the other hand, the do-while is always executed at least once, because the condition is not even checked until after the first execution of the loop body.
This flowchart illustrates the general logic of a trailing-decision loop. The body of the loop is executed at least once, because the condition test follows the body. A trailing-decision loop can also be implemented using a while loop, which is illustrated in the next exhibit.
Do...While Example
Suppose you want to verify that the user input was a positive number, and if they enter a negative or zero to keep prompting for correct input. Clearly, in this case you need to get the input before you test for the condition, therefore we need a do-while loop:
int age;
do{
String input = JOptionPane.showInputDialog("Please enter a value for age");
age = Integer.parseInt(input);
}while(age<=0); The general for of the do-while statement is:
do
statement
while(condition);Source Retrieved On,
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