my solutions--cc150 1.5

CompressStr.java

import java.util.*;

public class CompressStr {
	/**
	 * ask user for input and output the compressed string
	 * @param args
	 */
	 public static void main(String[] args){
	     Scanner input = new Scanner(System.in);
	     System.out.println("Please enter a string (q to quit): ");
	    	
	      while(input.hasNextLine()){
	    	 String userStr = input.nextLine();
	    	 if(userStr.equals("q")){
	    		 System.out.println("quit...");
	    		 System.exit(0);
	    	 }
	    	 System.out.println("The compressed string is " + compress(userStr));
	    	 System.out.println();
	    	 System.out.println("Please enter another string (q to quit): ");
	    		
	    }
	      
	 }
	 
	 /**
	  * compress the string if needed
	  * @param s
	  * @return compressed string
	  */
	 public static String compress(String s){
		 //tempCount to count number of char
		 int tempCount = 0;
		 //pointer to traverse the string
		 int i = 0;
		 StringBuffer result = new StringBuffer();
		 
		 
		 while(i < s.length()){
			 char tempChar = s.charAt(i);	 
			 while(s.charAt(i) == tempChar){
				 i++;
				 tempCount ++;
				 
				 //if ptr exceeds the length, call for final result
				 if(i >= s.length()){
					 result.append("" + tempChar + tempCount);
					 return decideStr(result.toString(), s);
				 }
			 }
			 //append the character and its frequency
			 result.append("" + tempChar + tempCount);
			 tempCount = 0;
		 }
		 
		 return decideStr(result.toString(), s);
 
	 }
	 
	 /**
	  * return the string of shorter length
	  * @param s1
	  * @param s2
	  * @return string of shorter length
	  */
	 public static String decideStr(String s1, String s2){
		 if(s1.length() < s2.length()){
			 return s1;
		 }else{
			 return s2;
		 }
		 
	 }
}