Task #1 Character and String Class Methods

1. Copy the files Time.java (Code Listing 9.1) and TimeDemo.java (Code Listing9.2) from the StudentCD or as directed by your instructor.

2. In the Time.java file, add conditions to the decision structure which validates the data. Conditions are needed that will:a).Check the length of the String b.) Check the position of the colon c.)Check that all other characters are digits.

3. Add lines that will separate the String into two substrings containing hours and minutes. Convert these substrings to integers and save them into the instance variables.

4. In the TimeDemo class, add a condition to the loop that converts the users answer to a capital letter prior to checking it.

5.Compile, debug, and run. Test out your program using the following valid input:

a.00:00 b.12:00 c.04:05 d.10:15 e.23:59 f.00:35

And the following invalid input:

a.7:56 b. 15:78 c.08:60 d. 24:00 e. 3e:33 f. 1:111

Time.java:

/** Represents time in hours and minutes using the customary conventions. */

public class Time { private int hours; // Conventional hours private int minutes; // Conventional minutes private boolean afternoon; // Flag for afternoon

/** Constructs a cutomary time (12 hours, am or pm) from a military time ##:## @param militaryTime Time in the military format ##:## */

public Time(String militaryTime) { // Check to make sure something was entered if (militaryTime == null) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } // Check to make sure there are 5 characters else if (// CONDITION TO CHECK LENGTH OF STRING) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else { // Check to make sure the colon is in // the correct spot if (//CONDITION TO CHECK COLON POSITION) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } // Check to make sure all other characters // are digits else if (// CONDITION TO CHECK FOR DIGIT) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else if (// CONDITION TO CHECK FOR DIGIT) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else if (//CONDITION TO CHECK FOR DIGIT) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else if (//CONDITION TO CHECK FOR DIGIT) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else { // SEPARATE THE STRING INTO THE HOURS // AND THE MINUTES, CONVERTING THEM TO // INTEGERS AND STORING INTO THE // INSTANCE VARIABLES

// Validate hours and minutes are valid values if(hours > 23) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } else if(minutes > 59) { System.out.println(militaryTime + " is not a " + "valid miliary time." ); } // Convert military time to conventional time // for afternoon times else if (hours > 12) { hours = hours - 12; afternoon = true; System.out.println(this.toString()); } // Account for midnight else if (hours == 0) { hours = 12; System.out.println(this.toString()); } // Account for noon else if (hours == 12) { afternoon = true; System.out.println(this.toString()); } // Morning times do not need converting else { System.out.println(this.toString()); } } } }

/** The toString method returns a conventional time. @return A conventional time with am or pm. */ public String toString() { String am_pm; String zero = "";

if (afternoon) am_pm = "PM"; else am_pm = "AM"; if (minutes < 10) zero = "0";

return hours + ":" + zero + minutes + " " + am_pm; } }

TimeDemo.java:

import java.util.Scanner;

/** This program demonstrates the Time class. */

public class TimeDemo { public static void main(String[] args) { Scanner keyboard = new Scanner(System.in); char answer = 'Y'; String enteredTime; String response;

while (//CHECK ANSWER AFTER CONVERTING TO CAPITAL) { System.out.print("Enter a military time " + "using the ##:## format: "); enteredTime = keyboard.nextLine(); Time now = new Time (enteredTime); System.out.println("Do you want to enter " + "another (Y/N)? "); response = keyboard.nextLine(); answer = response.charAt(0); } } }