CountDigits_Integer.js

let number = 1234567;

// Iterative Method
function countDigitsIterative(num) {
  let digits = 0;
  while (num) {
    // This condition becomes false when num becomes 0(zero)
    digits++;
    num = parseInt(num / 10);
    // Here, parseInt method is used to convert divided decimal number to integer, e.g. 126/10 = 12.6, parseInt(12.6) = 12
  }
  return digits;
}

console.log(countDigitsIterative(number)); // Output : 7

// Recursive Method
function countDigitsRecursive(num) {
  if (num === 0) {
    return 0;
  }
  return 1 + countDigitsRecursive(parseInt(num / 10));
}

console.log(countDigitsRecursive(number)); // Output : 7

// String Method
let strNum = number.toString(); // convert number to string , 1234 -> "1234"

console.log(strNum.length); // Output : 7

// Logarithm Approach
let logNum = 1 + Math.floor(Math.log10(number));

console.log(logNum); // Output : 7

// Not very useful but still a working approach
let numArr = strNum.split(""); // splitting a string and converting it into an Array , "1234" -> ["1", "2", "3", "4"]

console.log(numArr.length); // Output : 7