Sum of integers in a string-CodePudding

Here's my code:

function sumDigits(num) {

  var string = num.toString();
  var result = 0;

  for (let i = 0; i < string.length; i  ) {
    if (string[i] === '-') {
      var negative = Number(string[i   1]) * -1
      result = result   negative
    } else {
      result = result   Number(string[i])
    }
  }
  return result;
}

console.log(sumDigits('-316'))

When I add -316 as an argument, my output is 7. Why is it not taking -3 into the equation? As an FYI, I am still new to coding, and not sure this is even the correct route to take. All input is appreciated.

CodePudding user response：

Learn to debug, console.log and debugger are your friend.

function sumDigits(num) {

  var string = num.toString();
  var result = 0;
  console.log("my string:", string);

  for (let i = 0; i < string.length; i  ) {
    console.log("in loop", i, string[i]);
    if (string[i] === '-') {
      var negative = Number(string[i   1]) * -1
      console.log("in if ", result, " ", negative);
      result = result   negative
      console.log("updated result", result);
    } else {
      console.log("in else ", result, " ", Number(string[i]));
      result = result   Number(string[i])
      console.log("updated result", result);      
    }
  }
  console.log("final result", result);
  return result;

}

sumDigits(-317);

Looking at the results you can see you find a negative and you get the next number. On the next iteration you read that same number again. So -3 3 is zero. So you cancel it out. You need to skip your loop ahead by one.

function sumDigits(num) {

  var string = num.toString();
  var result = 0;
  for (let i = 0; i < string.length; i  ) {
    if (string[i] === '-') {
      var negative = Number(string[i   1]) * -1
      result = result   negative
      // bump i
      i  ;
    } else {
      result = result   Number(string[i])
    }
  }
  return result;

}

console.log(sumDigits(-317));

CodePudding user response：

I am checking whether the number is greater than 0 or less than zero.
Then if the number is less than zero, then I am merging the first element of array which will be (-digit) digits[0] = digits[0] digits[1];. -then I am removing 2nd element from digits array. digits.splice(1, 1);
And At the end I am lopping through all the digits using forEach loop and returning total of the dum digits to total.

const digitsSum = (number) => {

  let total = 0;
  if (number < 0) {
    let digits = number.toString().split('');
    digits[0] = digits[0]   digits[1];
    digits.splice(1, 1);
    digits.forEach(digit => total  = parseInt(digit));
    console.log(total);
    return total;
  } else {
    let digits = number.toString().split('');
    digits.forEach(digit => total  = parseInt(digit));
    console.log(total);
    return total;
  }
}

function calculateDigitSumLogic(number) {

}
digitsSum(-1203);
digitsSum(1203);
digitsSum(-201);