curriculum/challenges/english/blocks/learn-recursion-by-building-a-decimal-to-binary-converter/645b6dad50514e69df601df6.md
Now if you enter in the number 6 and click the Convert button, you'll see the following output:
Inputs: [ 6, 3, 1 ]
Quotients: [ 3, 1, 0 ]
Remainders: [ 0, 1, 1 ]
Notice that the remainders array is the binary representation of the number 6, but in reverse order.
Use the .reverse() method to reverse the order of the remainders array, and .join() with an empty string as a separator to join the elements into a binary number string. Then, set result.innerText equal to the binary number string.
You should use the .reverse() method on the remainders array.
assert.match(String(decimalToBinary), /remainders\.reverse\(\s*\)/);
You should use the .join() with an empty string as a separator on the reversed remainders array.
assert.match(String(decimalToBinary), /remainders\.reverse\(\s*\)\.join\(\s*('|"|`)\1\s*\)/);
You should set result.innerText equal to the binary number string.
const result = document.getElementById('result');
decimalToBinary(6);
assert.strictEqual(result.innerText.trim(), '110');
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Decimal to Binary Converter</title>
<link rel="stylesheet" href="styles.css" />
</head>
<body>
<h1>
Decimal to Binary
Converter
</h1>
<section class="input-container">
<label for="number-input">Enter a decimal number:</label>
<input
value=""
type="number"
name="decimal number input"
id="number-input"
class="number-input"
/>
<button class="convert-btn" id="convert-btn">Convert</button>
</section>
<section class="output-container">
<output id="result" for="number-input"></output>
<h2>Call stack</h2>
<div id="animation-container"></div>
</section>
<script src="script.js"></script>
</body>
</html>
*,
*::before,
*::after {
box-sizing: border-box;
margin: 0;
padding: 0;
}
:root {
--light-grey: #f5f6f7;
--dark-blue: #1b1b32;
--orange: #f1be32;
}
body {
display: flex;
flex-direction: column;
align-items: center;
font-family: Menlo, Consolas, Monaco, Liberation Mono, Lucida Console,
monospace;
font-size: 1.125rem;
color: var(--light-grey);
background-color: var(--dark-blue);
padding: 0 4px;
}
h1 {
font-size: 2.125rem;
text-align: center;
margin: 20px 0;
}
h2 {
font-size: 1.5rem;
text-align: center;
margin: 20px 0;
}
.input-container {
display: flex;
flex-direction: column;
gap: 10px;
justify-content: center;
align-items: center;
width: clamp(320px, 50vw, 460px);
margin: 10px auto;
}
.input-container label {
white-space: nowrap;
word-spacing: -6px;
}
.convert-btn {
font-size: inherit;
font-family: inherit;
background-color: var(--orange);
width: 100%;
height: 2rem;
padding: 0 6px;
border: none;
border-radius: 2px;
cursor: pointer;
}
.number-input {
font-size: inherit;
padding: 0.3rem;
width: 100%;
}
.output-container {
margin-inline: auto;
width: clamp(320px, 50vw, 460px);
}
#result {
display: flex;
align-items: center;
justify-content: center;
font-size: 2rem;
text-align: center;
min-height: 80px;
margin-block-start: 20px;
padding: 15px;
border: 2px solid var(--orange);
border-radius: 2px;
}
#animation-container {
display: flex;
flex-direction: column-reverse;
justify-content: end;
gap: 1rem;
margin-block-end: 1rem;
min-height: 40vh;
border: 2px dashed var(--orange);
padding: 1rem;
}
.animation-frame {
font-family: -apple-system, BlinkMacSystemFont, avenir next, avenir, segoe ui,
helvetica neue, helvetica, Cantarell, Ubuntu, roboto, noto, arial,
sans-serif;
padding: 15px 10px;
border: 5px solid var(--orange);
font-size: 1.2rem;
text-align: center;
}
@media screen and (min-width: 36em) {
body {
font-size: 1rem;
}
.input-container {
flex-direction: row;
width: unset;
}
.number-input {
width: unset;
}
}
const numberInput = document.getElementById("number-input");
const convertBtn = document.getElementById("convert-btn");
const result = document.getElementById("result");
const decimalToBinary = (input) => {
const inputs = [];
const quotients = [];
const remainders = [];
while (input > 0) {
const quotient = Math.floor(input / 2);
const remainder = input % 2;
inputs.push(input);
quotients.push(quotient);
remainders.push(remainder);
input = quotient;
}
console.log("Inputs: ", inputs);
console.log("Quotients: ", quotients);
console.log("Remainders: ", remainders);
--fcc-editable-region--
--fcc-editable-region--
};
const checkUserInput = () => {
if (
!numberInput.value ||
isNaN(parseInt(numberInput.value)) ||
parseInt(numberInput.value) < 0
) {
alert("Please provide a decimal number greater than or equal to 0");
return;
}
decimalToBinary(parseInt(numberInput.value));
numberInput.value = "";
};
convertBtn.addEventListener("click", checkUserInput);
numberInput.addEventListener("keydown", (e) => {
if (e.key === "Enter") {
checkUserInput();
}
});