Simple Mountain Cipher encryption of a plaintext file

MountainCipher.java

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class MountainCipher
{
	private int numberOfChars; // number of chars in the plaintext
	private int[] plainText; // array of plain text ASCII codes
	private int[] cipherText; // array of cipher text ASCII codes
	private String plainFile; // name of plaintext file
	private String cipherFile; // name of encrypted file
	
	public MountainCipher(String fileName1, String fileName2) throws IOException{
		plainFile = fileName1;
		cipherFile = fileName2;
		
		// create new BufferedReader to access the plainText file
		BufferedReader in = new BufferedReader(new FileReader(plainFile));
		
		numberOfChars = 0;
		while(in.read() != -1) { // stores number of chars in plainFile in int numberOfChars
			numberOfChars++;
		}
		in.close();
		
		plainText = new int[numberOfChars]; // allocate memory for plainText array
		cipherText = new int[numberOfChars]; // allocate memory for cipherText array
	}
	
	/**
	 * Read ASCII code of each char in plainFile and store values in plainText[] in pairs
	 */
	public void readPlainText() throws IOException{
		// create new BufferedReader to access the plainText file
		BufferedReader in = new BufferedReader(new FileReader(plainFile));
		
		for(int k = 0; k <= (numberOfChars - 1); k++) {
			plainText[k] = (int)in.read();
			System.out.println(plainText[k]);
			
		}
		
		in.close();
	}
	
	/**
	 * Encrypt every pair of ASCII codes in plainText and store in cipherText
	 */
	public void transform() {
		
	}
	
	
}