Prompt for array and counter

Question

Hello everyone I need help with my web scripting homework: Function: Counter Parameter: An array of Numbers. Returns: The numbers of negative, zeros, and positive numbers in the array Note: you must use a switch statement in the function. This is what I have so far

 <!DOCTYPE html>
 <head>
<title>Exercise 4.11</title>
</head>
<body>
<script>
    var num = new Array();
         num[0] = parseInt(prompt("Please enter a number",""),10);
         num[1] = parseInt(prompt("Please enter a number",""),10);
         num[2] = parseInt(prompt("Please enter a number",""),10);
         num[3] = parseInt(prompt("Please enter a number",""),10);
         num[4] = parseInt(prompt("Please enter a number",""),10);

counter(num);

function counter(num) {

    var i,
      count = {
        negative: 0,
        zero: 0,
        positive: 0,
    };

for(i = 0; i < num.length; i++) {
      switch (true) {
        case (num[i] < 0):
            count.negative++;
            break;

        case (num[i] === 0):
            count.zero++;
            break;

        case (num[i] > 0):
            count.positive++;
            break;

    }

}
document.write(count);
};
</script>
  </body>
</html>

I don't see a question here. What exactly are you having trouble with? — Zach H, Jun 23 '14 at 00:51
`return count; document.write(count);` ? Print it before returning or print the `counter` after the function — hlscalon, Jun 23 '14 at 00:55
Sorry everyone I wasn't very specific on what I needed thanks for you help so far but I am having trouble printing out the Negative, zero and positives from my counter — user3765781, Jun 23 '14 at 01:14
@user3765781 Sorry for being late to the party. I shared another (I find it better) example to achieve the needed. — Roko C. Buljan, Jun 23 '14 at 01:52

shennan · Accepted Answer · 2014-06-23T01:47:23.417

There are several things wrong with this, but as you've not really asked a question I'll address them at random.

you've created a method called counter for the task of processing the array, but you've not called it
you're attempting to document.write after you've already exited the method by calling return first.
your prompts will return strings, which need to be parsed into numbers using parseInt

A quick nudge in the right direction:

Call your counter method after you've prompted for the numbers, and change the syntax in the method declaration so that you can call it before it's defined:

var num = new Array();

num[0] = prompt("Please enter a number","");
num[1] = prompt("Please enter a number","");
num[2] = prompt("Please enter a number","");
num[3] = prompt("Please enter a number","");
num[4] = prompt("Please enter a number","");

counter(num);

function counter(num){

  // your logic

}

Update

At the end of your method, you'll want to print the results. As you've discovered, JavaScript is trying to describe the object you've asked it to print by converting it to a string. The string it ends up giving you is pretty uninsightful. What would be better is to print each individual key in the count object:

document.write(count.negative);
document.write(count.zero);
document.write(count.positive);

I would also look into using something other than document.write, but the reasons go beyond the scope of this question.

ok I see and then to print it out do I just document.write(count); at the end? I'm just getting [Object][object] as my output. — user3765781, Jun 23 '14 at 01:20
only a minor improvement, but use `var num = [];` instead. see http://stackoverflow.com/questions/931872/what-s-the-difference-between-array-and-while-declaring-a-javascript-ar — netzaffin, Jun 23 '14 at 08:56

Austin Mullins · Answer 2 · 2014-06-23T01:08:01.573

0

I'm going to guess that your problem is that the zero property of your counter object is always 0, because the prompt function returns a string not a number. The === operator only returns true if the two objects being compared are exactly the same, whereas the < and > operators are a bit more flexible. You should either call parseInt on the values returned by prompt, or change your case statement. Here are examples of the two options:

Option 1: ParseInt

num[0] = parseInt(prompt("Please enter a number",""), 10);

Option 2: Case Statement

case (num[i] == "0"):

These are two different approaches you could take. Do not combine them.

edited Jun 23 '14 at 01:08

answered Jun 23 '14 at 01:01

Austin Mullins

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I completely forgot about parseInt thank you for that. I am mostly just having troubles now printing the results out. – user3765781 Jun 23 '14 at 01:12
@Shennan's answer covers that as well. – Austin Mullins Jun 23 '14 at 01:13

Roko C. Buljan · Answer 3 · 2014-06-23T01:54:39.790

Hope I'm not late to the party. Here's my 2c:

jsBin demo

var count = {negative:0, zero:0, positive:0},
    i = 0 ;

(function ask(){
    var n = parseInt( prompt("Please enter a number",""), 10 );
    switch (true) {
      case (n<0):
        count.negative++;
        break;
      case (n===0):
        count.zero++;
        break;
      case (n>0):
        count.positive++;
        break;
      default: 
        alert( "Please use only Numbers!" );
        ask(); // Something went wrong... Ask again!
    }
    i++;
  if(i<5) ask();  // ASK 5 times

}()); // Start asking 

document.body.innerHTML = JSON.stringify(count, null, 4) ;

The above will immediately alert you if you did not used a number and repeat the process!
Also parseInt (10 is the radix param.) is needed to make sure to get a Number out of the prompt's String result.

Prompt for array and counter

3 Answers3

Option 1: ParseInt

Option 2: Case Statement