How to add number like 1+1+1=3 not "1"+"1"+"1" = 111 in javascript

Question

Here is my code:

var health = prompt("Type in health");
var attack = prompt("Type in attack");
var defense = prompt ("Type in defense");
function calculatestats(health,attack,defense){
    return health/4 + attack + defense
}
alert (calculatestats(health,attack,defense));

I want to make it output "3" when I type in 4, 1, and 1. The javascript is adding the characters, "1", "1", and "1". I want to add it Mathematically, and make it output 3, not 111. Thank you.

use parseInt https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt or parseFloat if you want to include floating point numbers. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseFloat — Andrew Lohr, Dec 19 '17 at 14:34

score 3 · Accepted Answer · answered Dec 19 '17 at 14:32

3

The prompt() returns a string. You have to do explicit type conversion using + or parseInt:

function calculatestats(health,attack,defense){
  return +health/4 + +attack + +defense;
}

Better way:

function calculatestats(health,attack,defense){
  return parseInt(health)/4 + parseInt(attack) + parseInt(defense);
}

answered Dec 19 '17 at 14:32

Soolie

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What does that + in front of "health/4", "attack", "defense" do? Also, what does parseInt do? Thanks. – Ardent Dec 19 '17 at 14:39
@Ardent Both do a type conversion from String to Integer... – Soolie Dec 19 '17 at 14:43
I had to wait for about 5 mins in order to accept the answer :^) – Ardent Dec 19 '17 at 14:51
@Ardent Thanks mate... Appreciated... – Soolie Dec 19 '17 at 14:52

How to add number like 1+1+1=3 not "1"+"1"+"1" = 111 in javascript

1 Answers1