Revers a string word by word without using inbuilt function in javascript

Question

function reverse1(str) {
  let r = "";
  for (let i = str.length - 1; i >= 0; i--) {
    r += str[i];
  }
  return r;
}

console.log(reverse1("I like this program very much"));

output: // hcum yrev margorp siht ekil I

but expected output: I ekil siht margorp yrev hcum

please can any one answer this....???

Answer 1

You are reversing the whole string. If you want to use a single function and assuming the string contains spaces only, you can loop through every character of the string.

If you encounter a space, you can append that to the result. If you encounter another character, you can prepend that to a temporary string to build a reversed version of the word.

Then append the reversed version of word to the result when the next character is either a space or when it is the last character in the iteration.

function reverse1(str) {
  let result = "", tmp = "";
  for (let i = 0; i < str.length; i++) {
    if (str[i] === ' ') {
      result += ' '; continue;
    }
    tmp = str[i] + tmp;
    if (str[i + 1] === undefined || str[i + 1] === ' ') {
      result += tmp; tmp = "";
    }
  }
  return result;
}

console.log(reverse1("I like this program very much"));
console.log(reverse1("    I like this program very much   "));
console.log(reverse1("abc"));