Caesars Cipher v252 SOLVED

JavaScript
#1

Tell us what’s happening:
Can’t figure out how to get the array or string from numbers back to letters. Ideas?

Your code so far

function rot13(str) { 
  var nArr = [];
  var number;
  var letter;
  for (i=0; i<str.length; i++){
  if (65 <= str.charCodeAt(i) && str.charCodeAt(i) <= 90){ //if it's between A-Z convert it
    number = str.charCodeAt(i)+13;  //convert + 13
    if (number > 90) {   //if the number is above 90 (Z) minus 26 to bring it down to range 65-90 (A-Z)
       number = number - 26;
    }
    letter = String.fromCharCode(number); //convert to letter
    nArr.push(letter); //push letters to array
   }
    else nArr.push(str[i]);
  }
  nArr = nArr.join('');
  return nArr;
}

// Change the inputs below to test
rot13("SERR CVMMN!");

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36.

Link to the challenge:
https://www.freecodecamp.org/challenges/caesars-cipher

#2
#3

nArr is an array and fromCharCode needs a string. I tried using .toString then fromCharCode but that didn’t work.

#4
  • fromCharCode() takes a number(s) as argument(s), not a string.
  • If you want to convert a whole array to a single string, you will want to use join().
#5

See updated code, I can convert everything fine. Now I need to make it if the number is over 90 (Z) then loop it back to A (65).

#6

That’s the logical bit that takes many people a little while to figure out.

#7

That’s the last part, right? What about another if statement? If the number is over 77 then do something special to it? If statements are so sloppy tho, must be a cleaner way.

#8

There’s nothing inherently wrong with if statements. They’re super useful. If you find yourself with an elaborate system of if/else statements, then you might want to restructure your logic.

#9

Code updated. The function is converting things that aren’t between 65 and 90, like ? and !. I can’t figure out why, ideas?

#10

I know why it seems like this should work, but you actually need to do
if (65 <= str.charCodeAt(i) && str.charCodeAt(i) <= 90)

You still won’t get the exact right solution. Only your letters will show up in your final result. Can you figure out why?

#11

I get “FREE4PIZZA10” as a result…I’m not sure how this is happening. Space is ASCII 32 and ! is ASCII 33, which are not in the range I specified.

#12

What is your current code?

#13

I had an i in the push method so it was pushing the position of the space (4) and the ! (10). Current code works, I just need it to push the spaces, ! and ? through.

#14

Current code works! Just needed to push the value at i if the first if statement didn’t work. Thanks man.

#15

Congratulations!

#16