Strategies for reversing strings in JavaScript without relying on built-in functions

Question

Strategies for reversing strings in JavaScript without relying on built-in functions

Are you wondering how to reverse the words in a string without using the split, reverse, and join functions?

Here is the problem: You need to reverse the words in a string. For example, if the input is "Hello World," the output should be "World Hello."

<script>
  var newString = ""; 
  var theString = prompt("Enter a Phrase that you would like to reverse (Ex. Hello world)"); 

  // Your code here

  document.write(newString);
</script>

Although you could easily achieve this using built-in methods, the challenge is to only use the following:

Arrays
Substring
charAt()

How would you approach this task?

javascript arrays substring charat

Answer 1

Answer №1

Alright, here's a technique you can use if you have the ability to utilize the charAt function to detect spaces between words. By identifying the spaces, you can then employ the substring method to extract and store each word separately in variables. After that, you can manipulate them and concatenate them back together. Let me demonstrate with an example:

var string = "Hello World",
    words = [],
    reversedString="",
    i;

for (i=0; i<string.length; i++) {
  if (string.charAt(i) === " ") {
    words.push(string.substring(0, i));
    words.push(string.substring(i));
  }
}

for (i=words.length-1; i>=0; i--) {
  reversedString += words[i];
}

Keep in mind that this is just a straightforward (untested) illustration and is tailored for a two-word string. If you wish to expand this to handle more words, you'll need to adjust the substring logic accordingly. I hope this guidance proves beneficial!

EDIT: I just realized that I forgot to reverse the string at the end; I've updated the code.

If you require further information, here are a couple of resources for your reference: substring charAt

Answer 2

Alright, here's a technique you can use if you have the ability to utilize the charAt function to detect spaces between words. By identifying the spaces, you can then employ the substring method to extract and store each word separately in variables. After that, you can manipulate them and concatenate them back together. Let me demonstrate with an example:

var string = "Hello World",
    words = [],
    reversedString="",
    i;

for (i=0; i<string.length; i++) {
  if (string.charAt(i) === " ") {
    words.push(string.substring(0, i));
    words.push(string.substring(i));
  }
}

for (i=words.length-1; i>=0; i--) {
  reversedString += words[i];
}

Keep in mind that this is just a straightforward (untested) illustration and is tailored for a two-word string. If you wish to expand this to handle more words, you'll need to adjust the substring logic accordingly. I hope this guidance proves beneficial!

EDIT: I just realized that I forgot to reverse the string at the end; I've updated the code.

If you require further information, here are a couple of resources for your reference: substring charAt

Strategies for reversing strings in JavaScript without relying on built-in functions

Answer №1

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