Q58.js

// 8. String to Integer (atoi)

// Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++'s atoi function).

// The algorithm for myAtoi(string s) is as follows:

// Read in and ignore any leading whitespace.
// Check if the next character (if not already at the end of the string) is '-' or '+'. Read this character in if it is either. This determines if the final result is negative or positive respectively. Assume the result is positive if neither is present.
// Read in next the characters until the next non-digit character or the end of the input is reached. The rest of the string is ignored.
// Convert these digits into an integer (i.e. "123" -> 123, "0032" -> 32). If no digits were read, then the integer is 0. Change the sign as necessary (from step 2).
// If the integer is out of the 32-bit signed integer range [-231, 231 - 1], then clamp the integer so that it remains in the range. Specifically, integers less than -231 should be clamped to -231, and integers greater than 231 - 1 should be clamped to 231 - 1.
// Return the integer as the final result.
// Note:

// Only the space character ' ' is considered a whitespace character.
// Do not ignore any characters other than the leading whitespace or the rest of the string after the digits.

function myAtoi(s) {
  s = parseInt(s);
  if (s > 2 ** 31 - 1) {
    return 2147483647;
  } else if (s < -1 * 2 ** 31) {
    return -2147483648;
  }
  if (isNaN(s)) {
    return 0
  }
  return s
}

let s = "words and 987";
console.log(myAtoi(s));