curriculum/challenges/english/blocks/learn-recursion-by-building-a-decimal-to-binary-converter/645b7f6a575ffc807877a8c6.md
Your decimalToBinary function works well, but there is an issue – because of the condition in your while loop, it only works for numbers greater than 0. If you try to convert 0 to binary, nothing will get added to the page.
To fix this, add an if statement to check if input is equal to 0. Leave the body of the if statement empty for now.
You should add an if statement that checks if input is equal to 0.
assert.match(String(decimalToBinary), /if\s*\(\s*input\s*===?\s*0\s*\)\s*\{/);
The body of your if statement should be empty.
assert.match(String(decimalToBinary), /if\s*\(\s*input\s*===?\s*0\s*\)\s*\{\s*\}/);
Your if statement should be written before your while loop.
assert.match(String(decimalToBinary), /if\s*\(\s*input\s*===?\s*0\s*\)\s*\{\s*\}[\s\S]*while\s*\(/);
<!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 = [];
--fcc-editable-region--
--fcc-editable-region--
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);
result.innerText = remainders.reverse().join("");
};
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();
}
});