Which LOOP
should I use???? |
-
while: the loop must repeat until a certain
"condition" is met. If the "condition" is FALSE at the
beginning of the loop, the loop is never executed. The "condition"
may be determined by the user at the keyboard. The "condition" may
be a numeric or an alphanumeric entry. This is a good, solid
looping process with applications to numerous situations.
-
do-while: operates under the same concept as the while loop except that the
do-while will always execute the body of
the loop at least one time. (Do-while is an
exit-condition loop -- the condition is checked at the end of the
loop.) This looping process is a good choice when you are asking
a question, whose answer will determine if the loop is repeated.
-
for: the loop is repeated a "specific" number of
times, determined by the program or the user. The loop
"counts" the number of times the body will be executed. This
loop is a good choice when the number of repetitions is known, or
can be supplied by the user.
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The following program fragments print the numbers 1 - 20.
Compare the different looping procedures. Remember, there are always MANY
possible ways to prepare code!
do-while:
int ctr = 1;
do
{
System.out.println(ctr);
ctr++;
}
while (ctr <= 20); |
for:
int ctr;
for(ctr=1;ctr<=20; ctr++)
{
System.out.println(ctr);
} |
while:
int ctr = 1;
while (ctr < = 20)
{
System.out.println(ctr);
ctr++;
} |
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