parseInt and Arrays [Novice]

#1
Dnectrum

Posted 03 December 2011 - 07:53 PM

Newbie

Members
9 posts

I am new to Javascript and this forum alike, so forgive me if I break any rules. I have searched the forum a bit, but to no avail.

My problem is that I currently am having troubling using parseInt and an array. The goal is to allow a user to enter a series of numbers and than pass those numbers to an array which would be able to run arithmetic off of them.

Am I using this properly?

<html>

 <head>

  <title> lab7 </title>

 </head>


 <body>

 <script>


 var nums = new Array();

 var integer;

 var sum;

 var average;

 var counter;

 var index = 1;

 var integer_count;

 var integer_total = 0;


 while (index <= 10)

 {

	nums[index] = prompt("Enter a number");

	nums[index] = parseInt(nums[index]);

	integer_total = integer_total + nums[index];

	index++;

 }


 average = integer_total / 10;

  

 index = 1;

 while (index <= 10)

 {

	if (nums[index] < average)

	{

		integer_count++;

	}

	index++

 }

 alert(average + integer_count);



 </script>

  

 </body>

</html>

#2
Orjan

Posted 04 December 2011 - 04:15 AM

Writes binary right handed and hex left handed

Moderators
3,299 posts

Location:Karlstad, Sweden
Programming Language:C, Java, C++, C#, PHP, JavaScript, Pascal
Learning:Java, C#

NaN stands for Not a Number. Check user input with isNaN to make sure it is a number before using it.

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I study Information Systems at Karlstad University when I'm not on CodeCall

#3
Dnectrum

Posted 04 December 2011 - 03:41 PM

Newbie

Members
9 posts

Okay thanks, but I am new so I really wouldn't know what to do with that just yet. Even if I check user input against isNaN, how could i go about changing the code to assure that workable numbers are being set in the array?

#4
Alexander

Posted 05 December 2011 - 03:21 AM

It's Science!

Moderators
4,118 posts

Location:Vancouver, Eh! Cleverness: 200

An idea of the top of my head, you can use the "continue;" statement if isNaN fails at the beginning of the while loop.

i.e. an array containing "14, 10, f, 40, 12"

(index) (integer)
1, 14
2, 10
(continue), f
3, 40
4, 12
...

This will leave you with nine numbers however, you will have to decide if you want to cause a failure, or to run the arithmetic with only nine (or less if more garbage) in the array.

Addendum: You may wish to start arrays at zero, as in your line of thinking, the first element starts at zero and takes place between zero and one. Having to off set your indexes from 1..10 can cause a lot of issues as the zeroth number can be garbage automatically if unassigned (I am not sure if uninitialisation occurs in Javascript however)

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