Java Tutorial/Statement Control/While Loop
Содержание
Java"s "labeled while" loop
<source lang="java">
public class MainClass {
public static void main(String[] args) {
int i = 0;
outer: while (true) {
System.out.println("Outer while loop");
while (true) {
i++;
System.out.println("i = " + i);
if (i == 1) {
System.out.println("continue");
continue;
}
if (i == 3) {
System.out.println("continue outer");
continue outer;
}
if (i == 5) {
System.out.println("break");
break;
}
if (i == 7) {
System.out.println("break outer");
break outer;
}
}
}
}
}</source>
Outer while loop i = 1 continue i = 2 i = 3 continue outer Outer while loop i = 4 i = 5 break Outer while loop i = 6 i = 7 break outer
The while Statement
- One way to create a loop is by using the while statement.
- Another way is to use the for statement
The while statement has the following syntax.
<source lang="java">
while (booleanExpression) {
statement (s)
}</source>
Using the while loop to calculate sum
<source lang="java">
public class MainClass {
public static void main(String[] args) {
int limit = 20;
int sum = 0;
int i = 1;
while (i <= limit) {
sum += i++;
}
System.out.println("sum = " + sum);
}
}</source>
sum = 210
While loop with double value
<source lang="java">
public class MainClass {
public static void main(String[] args) {
double r = 0;
while(r < 0.99d) {
r = Math.random();
System.out.println(r);
}
}
}</source>
0.4377278997305387 0.2688654455422754 0.36392537297385574 0.15254413511361042 0.6688621030424611 0.143156733550304 0.3867695752401421 0.6348496031126075 0.8262243996358971 0.057290108917235516 0.48887104413122007 0.9181002018325309 0.03580026338719999 0.6915245271034702 0.06281957479185263 0.7484170566879976 0.08309381253696246 0.7708638307798187 0.6586973690207539 0.3606321940413979 0.17404632324149583 0.1007512703731156 0.7971297767971545 0.4461084890266951 0.8627269068871244 0.04984737498714209 0.2597921665157922 0.5410470601800582 0.5779541886682865 0.1847556794086489 0.32127067165147705 0.12266607697656651 0.62729812639505 0.12191275953517977 0.72308829958122 0.5766115831015479 0.03444891261877858 0.3034596140603594 0.058872682884219985 0.85618745813345 0.07472991871327217 0.32676415639620604 0.6390549075075913 0.09246846051500635 0.9135703200463736 0.661365290176903 0.834153688687532 0.6340862529502882 0.3240420706550172 0.07246065490188025 0.35761285323105796 0.9964556875646731
