//UIUC CS125 SPRING 2016 MP. File: CaesarCipher.java, CS125 Project: Challenge3-TopSecret, Version: 2016-02-15T06:55:07-0600.622398463
/**
 * A program to search for to encrypt and decrypt lines of text. See
 * CaesarCipher.txt
 * Hints: line.charAt( int ) is useful.
 * You'll need loops, and conditions and variables
 * You'll need to read the Test cases to understand how your program should work.
 * Good Programming Hints: "DRY: Don't Repeat Yourself"
 * Try to make your program as short as possible.
 * TODO: add your netid to the line below
 * @author kosvick2
 */
public class CaesarCipher {

	public static void main(String[] strings) {
		boolean done=true;
		boolean fun=true;
		while(done){
			TextIO.putln("Please enter the shift value (between -25..-1 and 1..25)");
			int shift = TextIO.getlnInt();
			
			if(shift>=-25 && shift<=25 && shift!= 0) {
				TextIO.putln("Using shift value of " +shift);
				while(fun){
				TextIO.putln("Please enter the source text (empty line to quit)");
				String source = TextIO.getln();
				
				if(source.length()==0){
					TextIO.putln("Bye.");
					fun=false;
					done=false;
				}
				
				else {
					TextIO.putln("Source   :"+source);
					TextIO.put("Processed:");
					source = source.toUpperCase();
					char[] decode = source.toCharArray();
					
					for(int i=0; i<source.length(); i++){
						if((decode[i] >= 'A') && (decode[i] <= 'Z') && (decode[i]!= ' ')){
							decode[i] += shift;
					
							if((((decode[i]-'A')<0) || ((decode[i]-'A')<= 'Z')) && decode[i]!= ' ') {
								decode[i]= (char)((decode[i] - 'A' + 26)%26 + 'A');	
							}
						}
					TextIO.put(decode[i]);
					}
				}
			}	
			}	
				
			else {
			TextIO.putln(shift+ " is not a valid shift value.");
			}
	}

}
}