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01 Hello World!
02 Text I/O
03 Arithmetic
04 IF Statement
04 (b) Data Types
05 FOR Loop
06 Functions
07 While Loop
08 Do Loop
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Task Seven - While Loop - PHP Tutorial

This is the first program in this tutorial that carries out multiple tasks. It repeats until you type a zero to end the program. It expects you to enter a number and it prints a row of '*' characters where the length of the row is controlled by the number you enter. This program structure enables programs with a menu to be written. This program uses a "while" loop. There is more information about "while"loops here.

Here is the result of running the program.

Here is the program code.


<?php

// -----------------------------------------------------------------
// ----- This function returns a string consisting of $theChar -----
// ----- repeated $repCount times.                             -----
// -----------------------------------------------------------------
function repchar($theChar, $repCount)
{
  $s = "";

  for ($ii = 0; $ii < $repCount; $ii++)
  {
    $s = $s . $theChar;
  }

  return $s;
}
// -----------------------------------------------------------------

$run = True;

while ($run)
{
  echo "Enter a whole number (0 to quit) ... ";
  $num = fgets(STDIN);

  if ($num == 0)
  {
    $run = False;
  }
  else
  {
    echo(repchar("*", $num))."\n";
  }
}

// -----------------------------------------------------------------

?>

 

Code

Explanation

$run = True;

This is a Boolean. It is used to control the repetition of the while loop. As long as $run is true, the loop will keep repeating.

while ($run)
{
  // This block of code is repeated
  // as long as $run is true.
}

This is the structure of the while loop. The block of code inside the curly brackets is repeated as long as the Boolean, ($run) in this case, is true.

 

Learning Task

Write a program using a while loop and an IF statement to act as a menu. The menu choices should be

  • Press i or I to Insert
  • Press e or E Edit
  • Press d or D Delete
  • Press q or Q Quit

Write three functions named, insert, edit and delete. These are stub functions. They will not actually work but they act as place holders so you can set up the program structure. The functions should echo text to show they are present and working. Suitable text would be Insert, Edit and Delete.