Problem with Do While loop [Archive]

Wilund

05-08-2007, 05:12 PM

I am trying to make a program that either alerts or at least prints the multiples of a number (which the user inputs into a text field). I am required to use a do while loop for this, so here is what I have so far.

function factor() {
var number= document.form.text.value
var constant= document.form.text.value
do {
alert(number);
number= number+constant
} while (number <= 100);
}

// This line ends the HTML comment block -->

</SCRIPT>
</PRE>

<BODY>
<H1 align="center">Multiples<H1>
<H2 align="center">Please enter a number between 1-10.</H1>
<FORM name="form">
<CENTER>
<INPUT type="text" name="text">
<br>
<INPUT type="button" value="Show Multiples" onClick="factor();">
</CENTER>
</FORM>

Philip M

05-08-2007, 06:11 PM

Something like this?

<SCRIPT type = "Text/JavaScript">
function factor() {
var number= parseInt(document.form.text.value); // otherwise number is a string and 2+ 2 = 22
var mult = 0;
do {
mult ++;
result = number * mult;
alert ("Number is " + number + " Mult is " + mult + " Result is " + result);
} while (result <= 100);

}
</SCRIPT>

A do-while loop is often not a very good way of doing this sort of thing. A simple while loop is often better. Note that if result is 100 or less the loop will execute one more time, say 9 x 11 = 99, then 9 x 12 = 108. More generally, a do-while loop will always execute at least once as the test expression is not encountered until the end of the loop.