Enthuware

Code: Select all

public class Chapter6 {
    
    public void whichNumber(long num){
        
        if (num%2 == 0)
              System.out.println(num+" is an even number.");
        else
              System.out.println(num+" is an odd number.");
        
        System.out.println(num%2 == 0? num+" is an even number." : num+" is an odd number.");
    }
    
    public void whichNumber(double num){
        
        if (num%2 == 0)
              System.out.println(num+" is an even number.");
        else
              System.out.println(num+" is an odd number.");
        
        System.out.println(num%2 == 0? num+" is an even number." : num+" is an odd number.");
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
       Chapter6 t = new Chapter6();
       t.whichNumber(5.0f);
       t.whichNumber(244);
       t.whichNumber(6.5);
       t.whichNumber(2147483649L);

    }
    
}

Code: Select all

        int a = 0, b = 0, c = 0, d = 0;
        boolean flag = false;
        
        if (a == b) {
            if (c == 10) {
                if (d > a) {
                } else {
                }
                if (flag)
                    System.out.println("The first true flag check.");
                else 
                    System.out.println("The first false flag check.");
                
            } else if (flag == false) {
                System.out.println("The second flag check.");
            } else if (a + b < d) {
                System.out.println("");
            } else
                System.out.println("");
        } else
            d = b;

Code: Select all

        String[] word = {"hello", "goodbye", "well", "AA", "bad", "BBB", "last"};
        String[] rWord = new String[word.length];
        
        boolean alt = false;
        for (String s : word){
            if (!alt)
                System.out.print(s+" ");
            alt = !alt;
        }
        System.out.println();
        
        i = word.length - 1;
        for (String s : word){
            rWord[i] = s;
            i--;
        }
        for (String rs : rWord){
            System.out.print(rs+" ");
        }

Code: Select all

import student.*;
import static student.Student.*;


public class Course {
    
  
    static void enroll(Student x){ //all  the fields in the Student are public
        
        x.studentId = 2;
        name = "Bob";
        x.address = "222 Wrong Street"; 
        
        System.out.println(x.studentId);
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
               
               
    }
    
}

Code: Select all

package Ch10Ex;

public class Ch10Ex {
    
    int countVowels (char[] value) throws Exception {
        
        int vowelCt = 0;
        char ex6chk;

        if (value.length == 0)
            
            System.out.println("The array is empty.");
        
        else{

            try{

                ex6chk = value[0];  //Null Test

            }catch(ArrayIndexOutOfBoundsException iae){

                return 0;
            }            
        }
            
        for (char c : value){

                switch (c){

                    case 'a' : vowelCt += 1; break;
                    case 'e' : vowelCt += 1; break;
                    case 'o' : vowelCt += 1; break;
                    case 'i' : vowelCt += 1; break;
                    case 'u' : vowelCt += 1; break;
                    case 'x' : throw new Exception(); //Question 3

                    //below is unchecked verison which doesn't require a
                    //declaration in the throws clause.
                    //case 'x' : throw new IllegalArgumentException
                    //                     ("Array conatins'x'.");
                }
                
        }
        
                    try{        
                ex6chk = value[9];   //Less than 10 characters test 

            }catch(ArrayIndexOutOfBoundsException aiobe){

                //further enhancement to the original requirement.
                //see calling method.
                vowelCt = -vowelCt;
            }

        return vowelCt;
    }

    /**
     * @param args the command line arguments
     * @throws java.lang.Exception
     */
    public static void main(String[] args) throws Exception{
        
        Ch10Ex o = new Ch10Ex();
        
        int z;
        
        //test arrays for question 1
        char[] vc1 = {};
        char[] vc2 = {' '};
        char[] vc3 = {'e', 'g', 'i', '9', 's', 'o', 'd', 'e', '4', 'g'};
        
        z = o.countVowels(vc1);
        System.out.println("There are "+z+" vowels in the 1st array.");
    
        z = o.countVowels(vc2);
        System.out.println("There are "+z+" vowels in the 2nd array.");
        
        z = o.countVowels(vc3);
        System.out.println("There are "+z+" vowels in the 3rd array.");
      
        //Question 2
        for (int i = 0; i< args.length; i++) {
   
            char[] charInput = args[i].toCharArray();

            System.out.print("\nArray number "+i+": ");
            
            if (args[i].equals(" "))
                    System.out.print("This array only has blank characters.");
            
            for (char c: charInput)
                System.out.print(c+" ");

            try{
                int u;

                u = o.countVowels(charInput);

                if (u < 0) {
                    System.out.println("\nThe number of vowels is reset to "
                                       +"-1, since there are less than 10 "
                                       +"characters in the array. However"
                                       +" there are "+-u+" vowels in the"
                                       +" array.");
                    u = -1;
                }
                else
                    System.out.println("\nThere are "+u+" vowels in the "
                                       +"array.");
            }catch(Exception e){

                System.out.println("\nArgument number "+i+
                                   " contains character 'x'.");    
            }
      
        
        /*Question  4:
        -passing a null without a try/catch NPE, will cause JVM to throw one.
        */
        }
        
       //Question 5
        int n = 0;
        try{
            n = o.countVowels(null);
            
        //this catch clause satisfies both number 4 and 6 questions.
        }catch(IllegalArgumentException | NullPointerException ienpe){
                
           System.out.println("\nThe array is NULL, the number of vowels is "+
                              "set to "+n+".");
        }
    }
    
}