Question 306952 in Javascript Question posted in
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Javascript – Trouble Turning a For Loop Into a While Loop

I’m supposed to turn the following function into a while loop. The function is supposed to count all the e’s that appear in a certain string. Here’s the function using a for loop:

function eCounter(word) {
  let count = 0;

  for (let index = 0; index < word.length; index++) {
    let char = word[index];
    if (char === "e" || char === "E") {
      count += 1;
    }
  }

  return count;
};

Here’s my code:

function eCounter(word) {
  let count = 0
  let index = 0;
  let char = word[index];
  
while (char === "e" || char === "E") {
index+= count;
}
return count;
}
};

console.log(eCounter("apple")); // => 1
console.log(eCounter("appleapple")); // => 2
console.log(eCounter("Appleee")); // => 3

If count and index are both 0, and char is defined, I’m not sure what to do next. When I console.log the strings, all three return zero.

Any help I can get will be greatly appreciated.

I tried putting all of the code from the for loop into a while loop. I figured if I rearranged the for loop code into a while loop, it would return the number of e’s in each string. But when I run the code, all three counts return 0.

Tags:

3

Answers


  1. 0

    It’s similar to for loop

    function eCounter(word) {
  let count = 0
  let index = 0;
  while (index < word.length) {
    const char = word[index]
    if (char === "e" || char === "E") {
      count++
    }
    index++
  }
  return count;
}
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  2. 0

    try this

       function eCounter(word) {
  let count = 0
  let index = 0;
  let char = word.split('');
  
while (char[index]) {

if(char[index] === 'e' || char[index] === 'E'){
  count = count + 1;
}

index++;
}
return count;
}
};
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  3. 0

    Loop by the char index and increment it with ++ during reading the current character:

    function eCounter(word) {
  let count = 0, index = 0;
  while (index < word.length) {
    const char = word[index++];
    (char === "e" || char === "E") && count++;
  }
  return count;
}

console.log(eCounter('Evergrande'));

    Some more fancy variant:

    function eCounter(word) {
  let count = 0, index = 0, char;
  while (char = word[index++]) (char === "e" || char === "E") && count++;
  return count;
}

console.log(eCounter('Evergrande'));

    Can be even an one-liner:

    const eCounter = (word, index = 0, count = 0, char = null) => { while (char = word[index++]) (char === "e" || char === "E") && count++; return count};

console.log(eCounter('Evergrande'));

    Btw you can almost always replace the loop with Array::reduce:

    const eCounter = word => [...word].reduce((r, char) => char === "e" || char === "E" ? r + 1 : r, 0);

console.log(eCounter('Evergrande'));
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