Java Tutorial/Statement Control/While Loop

Java"s "labeled while" loop

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;
        }
      }
    }
  }
}

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

1. One way to create a loop is by using the while statement.
2. Another way is to use the for statement

The while statement has the following syntax.

while (booleanExpression) {
    statement (s)
}

Using the while loop to calculate sum

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);
  }
}

sum = 210

While loop with double value

public class MainClass {
  public static void main(String[] args) {
    double r = 0;
    while(r < 0.99d) {
      r = Math.random();
      System.out.println(r);
    }
  }
}

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0.6688621030424611
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0.35761285323105796
0.9964556875646731