JavaScript Algorithms and Data Structures Projects - Caesars Cipher

JavaScript
1

well this a caesars cipher project and its saying " Cannot read properties of undefined (reading ‘charCodeAt’)"

function rot13(str) {
  var solved = "";
  for( var i = 0; i <= str.length; i++) {
    var asciiNum = str[i].charCodeAt();

    if (asciiNum >= 65 && asciiNum <= 77) {
      solved += String.fromCharCode(asciiNum + 13)
    } else if (asciiNum >= 78 && asciiNum <= 90) {
      solved += String.fromCharCode(asciiNum - 13)
    } else {
      solved += str[i];
    }
  }
  return solved;
}

rot13("SERR PBQR PNZC");

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Challenge: JavaScript Algorithms and Data Structures Projects - Caesars Cipher

Link to the challenge:

2

You could check this out: str.length = 14

3

I played with your code a tad. two things you’ll need to change:

according to MDN, the format should be str.charCodeAt(i);

secondly, this part needs adjusting:

By the way, props for using the ascii methods. I didn’t think to check this when I passed this test

4

oh thanks…I researched methods to solve the problem and i stumbled on this way of solving it

5

did you get it to work? When I tried out your code, you were very close.

6

ya but when it prints to console it prints the wanted result with undefined at the end of the sentence

7

that’s because of this part

8

ok so from the for loop but what should it be

9

if i were representing an array, remember that arrays are zero-indexed. However, str.length is not.
what that means is if a string (lets say the word “string”) is 6 characters long, the index of the last letter would be 5 (it starts counting from zero.)
If you were to check the character at index 6, even though it’s 6 letters long, you get undefined as the answer because you’re checking an index that doesn’t exist.
TL;DR : arrays and .length are not exactly equal

10

ohhh thanks know i understand

11

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