Class help with character replacing?

[M. Mills]

Hi!
I have an assignment where I take input and search for and replace certain letters with others to create a code, and then I decode it. I'm confused about how to create create a loop to search for the letters. I know I use a if else statement inside the looping statement, but I don't know how to form it.

This is the file with the classes:

public class Crypto
{
    public static void main(String args[])
    { 
    }
    public String encrypt()
    {
        String firstEncrypt = "";
        for (int v = 0; v < firstEncrypt.length(); v++)
        {
            char firstLetter = firstEncrypt.charAt(v);
/*
I'm not sure how to replace the character either.
It has to be something like ag',r replaces v, but I always get "Unclosed character literal."
EDIT: Oops, sorry. I mean that I know all v's for example have to be replaced by ag'r, but I'm not exactly sure HOW.
*/
        }
        return firstEncrypt;
    }
    public String decrypt()
    { 
        String unEncryptOne = sntnc.replace('ag',r','v');
        return decryptedSntnc; 
    }
    public String sntnc;
    public String decryptedSntnc;
}

And here is the file that uses the classes:

import java.io.*;
import java.util.*;
public class Tester
{
    public static void main(String args[])
    {
        Scanner kbReader;
        new Scanner(System.in);
        System.out.print("Enter a sentence that is to be encrypted:");
        String sntnc = kbReader.nextLine();
        System.out.println("Original sentence = " + sntnc);
        
        Crypto myCryptObj = new Crypto();
        String encryptdSntnc = myCryptObj.encrypt(sntnc);
/*
This is the spot where I'm told that "encrypt() in Crypto cannot be applied to (java.lang.String)."
*/
        System.out.println("Encrypted sentence = " + encryptdSntnc);
        
        String decryptdSntnc = myCryptObj.decrypt(encryptdSntnc); [color=red]This is the other spot.[/color]
        System.out.println("Decrypted sentence = " + decryptdSntnc);
    }
}

Thank you so much!
[edit]Add code tags and change comments to /* */ type so as to fit width of screen. CR[/edit]

[Henry Wong]

It has to be something like ag',r replaces v, but I always get "Unclosed character literal."

Something like what??? Not sure what you are trying to write here.

String encryptdSntnc = myCryptObj.encrypt(sntnc); This is the spot where I'm told that "encrypt() in Crypto cannot be applied to (java.lang.String)."

Your encrypt() method doesn't take parameters -- it is called with a single string parameter here.

String decryptdSntnc = myCryptObj.decrypt(encryptdSntnc); This is the other spot.

Your decrypt() method doesn't take parameters -- it is called with a single string parameter here.

Henry

[M. Mills]

What exactly do you mean by a single string parameter?

[Henry Wong]

M. Mills wrote:What exactly do you mean by a single string parameter?

Your code.... calls the encrypt method... right here...

String sntnc = kbReader.nextLine();
System.out.println("Original sentence = " + sntnc);

Crypto myCryptObj = new Crypto();
String encryptdSntnc = myCryptObj.encrypt(sntnc);


Notice that you pass it a single parameter? Named sntnc? And notice that it is a string? .... aka a single string parameter?

Henry

[Campbell Ritchie]

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