Array, String, Data Structure to implement cesar algorithm?

Question

What is the best Data Structure(DS)/Class I can use to implement Caesar's Cipher ? This is what I have thought of so far:

String with all alphabets (abc...zABCD...Z) ?
Array with alphabets and wraparound ?
DS which stores a key value pair ?

Why i thought i need 3 - I have to find the character (which is to be encoded) in my "list of numbered alphabets". Then i use that index, and shift it by a number. I thought that it would be faster if i used key value pair instead of searching each index of string or array.

When you have your string to cipher just add the shift length to each character. Post your code, preferably a [sscce](http://sscce.org) for better help sooner. — jlordo, Jan 17 '13 at 08:56
You don't need to search each index, because the width of the shift is the same for all input characters. — jlordo, Jan 17 '13 at 08:58
@jlordo - actually, i have not implemented it yet. I need some help in deciding which of the 3 i have to use. Then, i will start coding. — FirstName LastName, Jan 17 '13 at 08:58
@FirstNameLastName: none of the three ;) See TechExchange's answer below. — jlordo, Jan 17 '13 at 08:59
oh ! this down vote is so depressing :( do i have to show example code all the time ? — FirstName LastName, Jan 17 '13 at 09:00

score 1 · Accepted Answer · answered Jan 17 '13 at 08:54

public String applyCaesar(String text, int shift)
{
    char[] chars = text.toCharArray();
    for (int i=0; i < text.length(); i++)
    {
        char c = chars[i];
        if (c >= 32 && c <= 127)
        {
            // Change base to make life easier, and use an
            // int explicitly to avoid worrying... cast later
            int x = c - 32;
            x = (x + shift) % 96;
            if (x < 0) 
              x += 96; //java modulo can lead to negative values!
            chars[i] = (char) (x + 32);
        }
    }
    return new String(chars);
}

as mentioned in this [answer](http://stackoverflow.com/questions/1821545/simple-caesar-cipher-in-java) — TheWhiteRabbit, Jan 17 '13 at 08:55

Array, String, Data Structure to implement cesar algorithm?

1 Answers1