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My teacher asked us to try and build a function that finds the longest length of a word in a string without using the str.split() method. the function should take a string as a parameter and and output the length of the longest word.

so far I have tried to make a function that puts the string into an array using the .push method then try to break up that array into each individual word and find the length of each word in each sub array and compare then. Because I am not smart or experienced enough to do this a friend of mine told me to try and :

> "just use two “tracking” variables. One to keep track of the current word and one to keep track of the longest word seen so far I will let you think about the initial values of what these should be. Next, it is just a matter of iterating through each character of str (strings are iterable just like arrays) to “build” a word. When you come across a space character or then end of str you know you have a complete word. You compare the length of this word with the current longest word (your other tracking variable) and assign the larger of the two to your longest word tracking variable. At the very end of the iteration your longest word tracking variable will contain the longest word length which you can return.Note: You will need to reset the word variable after you check it’s length, so it does not continue “building” through the rest of the iteration." >

I'm not really sure what he means or what to do.

so far I have this : 

function findLongestWordLength(str) {
    let words = []

    words.push(str);



    console.log(words)



}

findLongestWordLength("The quick brown fox jumped over the lazy dog");

what should I do ? I have the string pushed to an array but now that my friend has given me a hint I'm not sure what to do.

Quantsol
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  • You could use a loop to iterate through the string and check if the character is a space. – jro May 05 '19 at 00:04

2 Answers2

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Loop through each character in the string, adding to the current word. If you get to a space, check if your current word is longer than the previous longest word. If it is, store it. If it isn't, do nothing with it.

Clear out the current word and continue moving through the string.

function findLongestWordLength(str) {
  let longestWord = "";
  let currentWord = "";
  
  //Move through the string letter-by-letter
  for (let i = 0; i < str.length; i++) {
    if (str.charAt(i) === " ") { //If we're at a space character
      if (currentWord.length > longestWord.length) longestWord = currentWord; //Check if that word was the longest
      currentWord = ""; //Reset the current word
    } else {
      currentWord += str.charAt(i); //Not at a space character, still building the current word
    }
  }
  if (currentWord > longestWord) longestWord = currentWord; //End of string - check current word once more
  return longestWord;
}

const longest = findLongestWordLength("The quick brown fox jumped over the lazy dog");
console.log(longest);
Tyler Roper
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  • Perhaps a for...of loop is more appropriate since the index is unimportant – jro May 05 '19 at 00:21
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    Also this doesn't work with `findLongestWordLength("abcedfg")` – jro May 05 '19 at 00:24
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    @jro You're right, thank you. I've updated the answer to address that. I agree with your first point as well, but given that OP is still learning, I personally think that the basic `for` loop is the most appropriate. – Tyler Roper May 05 '19 at 00:26
  • @Quantsol I believe I've already done that... Is there something I haven't commented that you aren't sure about? – Tyler Roper May 05 '19 at 00:28
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Probably a shorter and quicker way is to use a simple regex like this

function findLongestWordLength( str ) {
  var longestWord = "";
  str.replace( /\S+/g, function( match ) {
        if ( match.length > longestWord.length )
          longestWord = match;
      }
    ); 
    return longestWord;  // .length; 
 }

console.log( findLongestWordLength("The quick brown fox jumped over the lazy dog") );