Average calculator finding strange and incorrect numbers

Question

I am trying to make an average calculator. This is my code for it:

var data = [];
var yesno = confirm("Would you like to add more data?");
while (yesno) {
   var newdata = prompt("Enter a piece of data (must be a number)");
   data.push(newdata);
   var yesno = confirm("Would you like to add more data?");
}
var total = 0;
var i = 0;
if (!yesno) {
   while (i < data.length) {
      total += data[i];
      i++;
   }
}
var average = total / data.length;
document.write(average);

It seems to take input well, however something goes wrong when it comes to calculation. It says that the average of 6 and 6 is 33, 2 and 2 is 11, and 12 and 6 is 306. These are obviously wrong. Thank you in advance for your help.

newdata taken from user is string..should be converted to Number ! — Gourishankar, Jun 02 '19 at 10:53

score 3 · Answer 1 · answered Jun 02 '19 at 10:48

3

You need to take a number, not a string value from the prompt.

The easiest was is to take an unary plus + for converting a number as string to a number

data.push(+newdata);
//        ^

Your first example shows, with '6' plus '6', you get '66', instead of 12. The later divsion converts the value to a number, but you get a wrong result with it.

answered Jun 02 '19 at 10:48

Nina Scholz

376,160
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A little more information about why the behavior is the way it is wouldn't hurt. – Andreas Jun 02 '19 at 10:52
And bonus points for an explanation for the last example: `'12' + '6' -> 306` – Andreas Jun 02 '19 at 10:53
the last, i don't know ... – Nina Scholz Jun 02 '19 at 10:59
OP probably made a typo in the question, tested out the exact code, fed in 12 and 6, returned the expected result of 63. – Lorddirt Jun 02 '19 at 11:30
I didn’t make a typo; I ran it again and got the same result (with broken code) – Coder66 Jun 02 '19 at 11:51
Last one is `6 and 12`. OP got the order mixed. `'6' + '12' = '612'` and `612 / 2 = 306`. – Sani Huttunen Jun 02 '19 at 18:52

score 1 · Accepted Answer · answered Jun 02 '19 at 11:30

1

It is taking the input as string. Convert the input to floats before putting them in the array. I think its performing string additions like 6+6=66 and then 66/2 = 33. Similar is the case of 2 and 2.

answered Jun 02 '19 at 11:30

vizsatiz

1,933
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Average calculator finding strange and incorrect numbers

2 Answers2