How to code the iteration structures

A while loop that finds the average of 100 random numbers

      $total = 0; $count = 0;

      while ($count < 100) {

        $number = mt_rand(0, 100); // get a random number from 0 to 100

        $total += $number; $count++;

      }

      $average = $total / $count;

      echo("<p>The total of $count random numbers is " . number_format($total) . " and the average is: " . number_format($average, 2) . "</p>>\n");
      The total of 100 random numbers is 4,761 and the average is: 47.61

A while loop that counts dice rolls until a six is rolled

       $rolls = 1;

       while (mt_rand(1,6) != 6) { // get a random number from 1 to 6

         $rolls++;

       }

       echo("<p>Number of times to roll a six: $rolls.</p>\n");
      Number of times to roll a six: 5.

Nested while loops that get the average and maximum rolls

      $total = 0;

      $count = 0;

      $max = -INF;

      while ($count < 10000) {

        $rolls = 1;

        while (mt_rand(1, 6) != 6) { // get a random number from 1 to 6

          $rolls++;

        }

        $total += $rolls;

        $count++;

        $max = max($rolls, $max); // get the value of the larger argument

        $average = $total / $count;

      }

      echo("<p>Average: $average Max: $max;</p>\n");
      Average: 5.9984 Max: 47;

The while statement executes the block of statements within its braces as long as its conditional expression is TRUE.
When you use a while statement, the condition is tested before the while loop is executed.
Note:These examples use the mt_rand() and max() functions, which are presented in the next chapter.

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