Learn Recursion by Building a Decimal to Binary Converter - Step 69

JavaScript
1

Tell us what’s happening:

Describe your issue in detail here.
Why is your auto coder saying this is wrong?
return decimalToBinary(Math.floor(input / 2) + (Math.floor(input / 2) % 2));

Your code so far

const numberInput = document.getElementById(“number-input”);
const convertBtn = document.getElementById(“convert-btn”);
const result = document.getElementById(“result”);

const decimalToBinary = (input) => {
if (input === 0) {
return “”;
} else {
// the recursive case
return decimalToBinary(Math.floor(input / 2) + (Math.floor(input / 2) % 2));
}

};

const checkUserInput = () => {
// checking for empty string which is faulsy, or not an integer with parseInt wrapped in isNaN
if (!numberInput.value || isNaN(parseInt(numberInput.value))) {
alert(“Please provide a decimal number”);
return;
}
decimalToBinary(parseInt(numberInput.value));
numberInput.value = “”;
};

convertBtn.addEventListener(“click”, checkUserInput);
numberInput.addEventListener(“keydown”, (e) => {
if (e.key === “Enter”) {
checkUserInput();
}
});

<!-- file: index.html -->
<!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>
    <div 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>
    </div>
    <output id="result" for="number-input"></output>
    <div id="animation-container"></div>
    <script src="script.js"></script>
  </body>
</html>

/* file: styles.css */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --light-grey: #f5f6f7;
  --dark-blue: #1b1b32;
  --orange: #f1be32;
}

body {
  background-color: var(--dark-blue);
  font-family: "Times New Roman", Times, serif;
  font-size: 18px;
  color: var(--light-grey);
  padding: 0 15px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

h1 {
  text-align: center;
  font-size: 2.3rem;
  margin: 20px 0;
}

.input-container {
  margin: 10px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: center;
  align-items: center;
}

.convert-btn {
  background-color: var(--orange);
  cursor: pointer;
  border: none;
  padding: 4px;
}

.number-input {
  height: 25px;
}

#result {
  margin: 10px 0;
  min-width: 200px;
  width: fit-content;
  min-height: 80px;
  word-break: break-word;
  padding: 15px;
  border: 5px solid var(--orange);
  font-size: 2rem;
  text-align: center;
}

#animation-container {
  margin: auto;
  max-width: 300px;
}

.animation-frame {
  margin: 250px auto 0;
  padding: 15px 10px;
  border: 5px solid var(--orange);
  font-size: 1.2rem;
  text-align: center;
}

@media screen and (min-width: 500px) {
  .input-container {
    flex-direction: row;
  }

  #result {
    max-width: 460px;
  }
}

/* file: script.js */
const numberInput = document.getElementById("number-input");
const convertBtn = document.getElementById("convert-btn");
const result = document.getElementById("result");

const decimalToBinary = (input) => {
  if (input === 0) {
    return "";
  } else {

// User Editable Region

    return decimalToBinary(Math.floor(input / 2) + (Math.floor(input / 2) % 2));

// User Editable Region

  }
};

const checkUserInput = () => {
  if (!numberInput.value || isNaN(parseInt(numberInput.value))) {
    alert("Please provide a decimal number");
    return;
  }

  decimalToBinary(parseInt(numberInput.value));
  numberInput.value = "";
};

convertBtn.addEventListener("click", checkUserInput);

numberInput.addEventListener("keydown", (e) => {
  if (e.key === "Enter") {
    checkUserInput();
  }
});

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Challenge Information:

Learn Recursion by Building a Decimal to Binary Converter - Step 69

2

You appear to have created this post without editing the template. Please edit your post to Tell us what’s happening in your own words.

3

This concatenated value isn’t quite what the instructions are asking for:

concatenate the remainder of input divided by 2

You don’t need to use a / operator as the modulo (%) operator does that for you. You don’t need Math.floor() here either.

4

Hi - thanks for your reply on which I based changing the code to this which also is not working… :
const decimalToBinary = (input) => {
if (input === 0) {
return “”;
} else {
return decimalToBinary(Math.floor(input / 2) + (input % 2));
}
};

1 Like
5

You’re close but you just need to move the concatenated bit outside of the decimalToBinary parentheses as you don’t want the function to act on that bit of the code.

2 Likes
6

This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.