CodeEval - Roller Coaster - Easy

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws FileNotFoundException, IOException {

    File file = new File(args[0]);
    BufferedReader in = new BufferedReader(new FileReader(file));
        StringBuffer sb=new StringBuffer();
        String line;
        while ((line = in.readLine()) != null) {
            boolean upperCase=true;
            for(int i=0;i<line.length();i++){
               char c=line.charAt(i);
               if(c>='a' &&c<='z'){
                   if(upperCase){
                      sb.append((char)(c-32));
                   }else{
                       sb.append(c);
                   }
                   upperCase=!upperCase;
               }else if(c>='A'&&c<='Z'){
                   if(!upperCase){
                      sb.append((char)(c+32));
                   }else{
                       sb.append(c);
                   }
                   upperCase=!upperCase;
               }else{
                   sb.append(c);
               }
            }
            sb.append('\n');
        }
        System.out.print(sb);
    }
   
}