Alexander Barakov - 7 months ago 51

Javascript Question

I just started studying JavaScrpt and tried to make code to calculate math formula but it doesn't work as I expected. Here's the code I'm working on. When I run the code if I type 2 in A 3 in B and 4 in C by the formula B^2 - 4 * A * C it should return -23 but it returns -31. Can someone more experienced take a look and tell me where is my mistake?

`<html>`

<head>

</head>

<body>

<form id="reshenie" action="">

<fieldset>

<p>

<label for="A">a</label>

<input id="A" name="A" type="number" />

</p>

<p>

<label for="B">b</label>

<input id="B" name="B" type="number" />

</p>

<p>

<label for="C">c</label>

<input id="C" name="C" type="number" />

</p>

<p>

<input type="submit" value="submit" />

<input type="reset" value="reset" />

</p>

<p>

<label for="result">result</label>

<input id="result" name="result" type="number" />

</p>

</fieldset>

</form>

<script>

(function () {

function presmqtane(A,B,C) {

A = parseFloat(A);

B = parseFloat(B);

C = parseFloat(C);

return (B^2 - 4 * A * C);

}

var reshenie = document.getElementById("reshenie");

if (reshenie) {

reshenie.onsubmit = function () {

this.result.value = presmqtane(this.A.value, this.B.value, this.C.value);

return false;

};

}

}());

</script>

</body>

</html>

Answer

Welcome to StackOverflow! I'm guessing that when you wrote this:

```
return (B^2 - 4 * A * C);
```

You meant this:

```
return (Math.pow(B, 2) - 4 * A * C);
```

The `^`

symbol is the `XOR`

operator, not the exponentiation. There is no symbol for that, only `Math.pow()`

.

Also note that variable names, in Javascript, are usually written un lower-case. I would use `a`

, `b`

, `c`

instead of `A`

, `B`

, `C`

(which traditionally represent classes, not objects). This also plays along with the mathematical standard (I'm assuming that's the quadratic closed equation), where upper-case letters usually represent objects more complex than numbers, such as matrices or graphs.

Source (Stackoverflow)