Reverse Integer

Challenge Description

Given an integer, reverse its digits and return the result. For example:

• 1234 becomes 4321
• -5678 becomes -8765

Tips to Solve

tip

1. Convert the number to a string using the toString method.
2. Convert the string to an array using the split method.
3. Reverse the array using the reverse method.
4. Convert the array back to a string using the join method.
5. Convert the string back to a number using the parseInt method.
6. Maintain the sign of the original number.

Step-by-Step Solution

Let's break down the solution into easy steps:

1. Convert the Number to a String: Use the toString method to convert the number into a string.

   const str = (1234).toString(); // "1234"

2. Convert the String to an Array: Use the split method to convert the string into an array of characters.

   const strArray = str.split(""); // ["1", "2", "3", "4"]

3. Reverse the Array: Use the reverse method to reverse the order of the elements in the array.

   const reversedArray = strArray.reverse(); // ["4", "3", "2", "1"]

4. Convert the Array Back to a String: Use the join method to combine the elements of the array back into a string.

   const reversedString = reversedArray.join(""); // "4321"

5. Convert the String to a Number: Use the parseInt method to convert the string back into a number.

   const reversedNumber = parseInt(reversedString); // 4321

6. Maintain the Sign: Multiply the reversed number by the sign of the original number to maintain its sign.

   const finalNumber = reversedNumber * Math.sign(1234); // 4321

Full Solution Code

Here is the complete solution using the steps above:

const reverseInt = (n) => {
  const reversed = n.toString().split("").reverse().join("");
  return parseInt(reversed) * Math.sign(n);
};

console.log(reverseInt(1234)); // Output: 4321
console.log(reverseInt(-5678)); // Output: -8765
console.log(reverseInt(0)); // Output: 0