StringAllUniqueChar.java

package stringalluniquechar;

import java.util.Scanner;
/**
 *
 * @author JOSEPH CONQUEST
 * String All Unique Char reads a String from command prompt
 * And determines if the string contains any duplicate chars
 * Printing out the result to the command prompt
 */
public class StringAllUniqueChar {

 /**
 * @param args the command line arguments
 */
 public static void main(String[] args) {
 //Test case for array analysis
 Scanner keyboard = new Scanner(System.in);
 System.out.println("Please enter the string you want analyzed with "
 + "arrayAnalysis");
 String input = keyboard.nextLine();
 System.out.println("You enetered the following string : "+input);
 boolean duplicatesNotFound = arrayAnalysis(input);
 System.out.println("Using arrayAnalysis determined the following: ");
 if(!duplicatesNotFound) System.out.println("Duplicates were found");
 else System.out.println("Duplicates were not found"); 
 //Test case for comparative analysis
 System.out.println("Please enter the string you want analyzed with "
 + "arrayAnalysis");
 input = keyboard.nextLine();
 System.out.println("You enetered the following string : "+input);
 boolean duplicatesNotFound2 = arrayAnalysis(input);
 System.out.println("Using comparativeAnalysis determined "
 + "the following: ");
 if(!duplicatesNotFound2) System.out.println("Duplicates were found");
 else System.out.println("Duplicates were not found"); 
 }
 /*
 * Method takes in a string "in" for a parameter and anaylzes in for any
 * duplicate chars. Method uses array of int to anaylze duplication,
 * requiring extra overhead for execution but providing O(n) to analyze
 * RETURN If a duplicate is found, the method returns false
 */ 
 public static boolean arrayAnalysis(String in){
 boolean duplicateNotFound = true;
 int[] array = new int[127];
 for(int j = 0; j < in.length(); j ++){ //for each char in string
 char current = in.charAt(j);
 array[current]++;//
 if ( array[current] > 1){
 duplicateNotFound = false;
 break;
 }
 } 
 return duplicateNotFound;
 }
 /*
 * Method takes in a string "in" for a parameter and anaylzes in for any
 * duplicate chars. Method compares each char to every other char of in,
 * requiring O(n^2) to analyze, but not requiring data structure overhead
 * RETURN If a duplicate is found, the method returns false
 */ 
 public static boolean comparativeAnalysis(String in){
 boolean duplicateNotFound = true;
 for (int i = 0; i < in.length(); i++){ //for each char in string
 char current = in.charAt(i);
 //check all other chars for duplicates
 for(int j = 0; j < in.length(); j++){ 
 if(j != i){ //do not compare current to itself
 char compare = in.charAt(j);
 if (compare == current) return false;
 } 
 }
 }
 return duplicateNotFound;
 }
 
}