Why this function doesn't work?

Question

var f = prompt ("first number:", );// if you enter 2
var l = prompt ("last number:", );//if you enter 20
var s = prompt ("length of sequence:", );// if you enter 10
function Arithm(a, A, n) {
var sum = (a + A)/2*n
return sum;
}//Why
alert(Arithm(f, l, s));// this doesn't work

alert(Arithm(2, 20, 10));// like this?

Answer 1

Bear parseInt(<number>); is for make integer from a (float) number

Like try out this (insert to JS Tab):

window.onload=function test()
{
var x = 26.4;
var y = parseInt(x);

alert(y);
}

😃

Answer 2

Iryna Yudina remove "," from your prompt() function. You don't need "," after the "question-text. So var f = prompt ("question") ; --> and done.

Try this:
var f = prompt ("first number:" );// if you enter 2
var l = prompt ("last number:" );//if you enter 20
var s = prompt ("length of sequence:" );// if you enter 10
function Arithm(a, A, n) {
var sum = (a + A)/2*n
return sum;
}//Why
alert(Arithm(f, l, s));// this doesn't work

alert(Arithm(2, 20, 10));// like this?

Answer 3

I figured it out.
I just had to add + before prompts to convert them into a numbers. Like
var f = +prompt (....);
Now it works correctly.

Answer 4

You have to grave the value like this.
var first = f.value;
var last = l.value;
var seq = s.value;

Then you can use it in function. Like alert(Arithm(first,last,seq)) 😒✌

Answer 5

That is great 😆

Answer 6

I think you can also use parseInt() to convert the input into numbers. Not sure though...