The Do Statement
The 'do-while' loop is a variation of the while loop. 'do-while' loops always execute at least once, whereas while loops may never execute.
3. Bottom-driven Loop
Answer:
Yes.
Bottom-driven Loop
All loops must do three things:
- The loop must be initialized correctly.
- The ending condition must be tested correctly.
- The body of the loop must change the condition that is tested.
The code fragment includes all three, but in a different order than usual. The ending condition test is done after the loop body has executed.
int count = 0; // initialize count to 0 do { System.out.println( count ); // loop body: includes code to count++ ; // change the count } while ( count < 10 ); // test if the loop body should be // executed again. |
Loops with the test at the top of the loop (while
and for
loops) are called top-driven loops.
Loops implemented with the test at the bottom (a do
loop) are called bottom-driven loops. This location for the test has some odd (and sometimes undesirable) effects. Examine the following:
int count = 1000; do { System.out.println( count ); count++ ; } while ( count < 10 ); |
Question 3:
What is the output of the revised loop?