Caesars Cipher - fromCharCode issues

Tell us what’s happening:
When I console.log newstring. I get the correct values for free code camp.


When I try to feed this to fromCharCode it doesn’t seem to function correctly:

Any idea why the fromCharCode isn’t working as expected?

Thanks again!

Your code so far

function rot13(str) { // LBH QVQ VG!
  var newstring ="";
  for (var index =0; index < str.length; index++){
  if (str.charCodeAt(index) >= 78){
    newstring += str.charCodeAt(index) - 13 + ",";
  if ((str.charCodeAt(index) < 78) && (str.charCodeAt(index) !=32)){
    var difference = 0;
    var from13 = 0;
    difference = str.charCodeAt(index) - 64;
    from13 = 13 - difference;
    newstring += 90 - from13 + ",";
    if(str.charCodeAt(index)== 32){
      newstring += 32 + ",";
  var translated = String.fromCharCode(newstring);
  return str;

// Change the inputs below to test
rot13("SERR PBQR PNZC");

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Link to the challenge:

When you write:

var translated = String.fromCharCode(newstring);

you have to remember that newstring is a string of number characters separated by commas. String.fromCharCode expects a number to be passed to it. You are passing a string and not a number.

1 Like

Thanks. I thought I could just pass that into fromCharCode (maybe auto conversion?). Any hints on how to convert it? It seems to accept comma separated numbers.

Iterate through the string and get one number at a time or store the numbers in an array and do the same.

1 Like

Thanks again. That’s what I ended up doing and then converting it to a number with It worked.