So basically my objective is to make a program that takes the user input and reverses it and prints the inverse character back to user as an encoded message. Right now i need to print the statistics of the user entered string. How do i count the amount of occurrences of different letters from the user string. I have this so far.
import java.util.*;
public class SecretCodeMachine
{
public static void main(String[]args)
{
//object accessing the non static methods
SecretCodeMachine a = new SecretCodeMachine();
//input stream
Scanner in = new Scanner (System.in);
Scanner i = new Scanner (System.in);
//prompt the user
System.out.println("Please input your secret message.");
String input = in.nextLine();
//calls the encodedMessage() method; equals the return value to varaible
String encodedMessage = a.encodeMessage(input);
//message and prompt
System.out.println("Encoded message: " + encodedMessage);
System.out.println("Enter the code in here to get the original message back.");
String input2 = i.nextLine();
//if statements saying that if the input equals the encoed message...
if (input2.equals(encodedMessage))
{
//print this
System.out.println("Original Message: " + input);
}
else
{
//prints when doesnt equal
System.out.println("Message not found.");
}
//closes the input stream
i.close();
in.close();
}
//method for encoding the string from array
public String encodeMessage(String pass)
{
//passes the parameter string and puts it in an array ()
char[] toArray = pass.toCharArray();
for (int i = 0; i < toArray.length; i++)
{
//does the lower case characters
if (toArray[i] >= 'a' && toArray[i] <= 'z')
{
if (toArray[i] - 'a' <= 13) toArray[i] = (char) ('z' - (toArray[i] - 'a'));
else toArray[i] = (char) ('a' + ('z' - toArray[i]));
}
//does the upper case characters
else if(toArray[i] >= 'A' && toArray[i] <= 'Z')
{
if (toArray[i] - 'A' <= 13) toArray[i] = (char) ('Z' - (toArray[i] - 'A'));
else toArray[i] = (char) ('A' + ('Z' - toArray[i]));
}
//if the characters are non alphatbetic
else
{
toArray[i] = toArray[i];
}
}
//converts the toArray back to new string
String encodedMessage = new String(toArray);
//returns the encodedMessage string
return encodedMessage;
}
}
So how would i keep a track off all the letters that are entered by the user?
public class SecretCodeMachine
{
HashMap<Character, Integer> charCounts = new HashMap<Character, Integer>();//add hashmap here
Code for updating count for each character:
for (int i = 0; i < toArray.length; i++)
{
//does the lower case characters
//update count for character
if(charCounts.get(toArray[i]) != null)
{
charCounts.put(toArray[i], (charCounts.get(toArray[i]) + 1));
}
else
{
charCounts.put(toArray[i], 1);
}
if (toArray[i] >= 'a' && toArray[i] <= 'z')
{
if (toArray[i] - 'a' <= 13) toArray[i] = (char) ('z' - (toArray[i] - 'a'));
else toArray[i] = (char) ('a' + ('z' - toArray[i]));
}
//does the upper case characters
else if(toArray[i] >= 'A' && toArray[i] <= 'Z')
{
if (toArray[i] - 'A' <= 13) toArray[i] = (char) ('Z' - (toArray[i] - 'A'));
else toArray[i] = (char) ('A' + ('Z' - toArray[i]));
}
//if the characters are non alphatbetic
else
{
toArray[i] = toArray[i];
}
}
You could use a hashmap to store characters and integers. Key/Value pair only one entry for each key per map. Example