While

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layout: default title: while Loop

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The while loop allows us to repeat a section of code as long as a condition is true.

int num = 0;
while (num < 5) {
  System.out.println("num is " + num);
  num = num + 1;
}    

1. The program checks the condition num < 5 to see if it should run the loop.

1. If so, it executes the statements in the { }

2. We call these statements the loop body.

3. The program then "loops" back to the while statement to check the condition again.

loop body

The simple statement or block that's controlled by a loop statement.

As long as num is less than 5, this loop will keep executing.

This loop will print the values 0 through 4.

• When num is finally 5, the loop will no longer execute (because 5 is not less than 5).

Drill

WhileLoops/src/drills/WhileLoop.java This class has two methods which are called from main. Write the code in the methods. * printNumbers() - Write a while loop to print the numbers 1 to 10 to the screen. * mathRandomWhile() - Use Math.random() to write a while loop that will execute as long as a random number is less than 0.7. Print the number inside the loop. Example: double d = Math.random(); Make sure to reassign d to a new Math.random() value in the loop body. After the loop, add a statement to print the final value of d. (You may have to run it a few times to see output.)

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