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I need to create a DVD inventory that can do the things listed in the code. I think i need to use a linked list for the inventory list, but i don't know how linked lists work. can someone help me?
CODE
import java.util.Scanner; // import Scanner public class DVD {
public static void main(String[] args) { Scanner input = new Scanner( System.in ); // create Scanner String command; String newTitle; int newWant; int newHave; int quit;
System.out.println( "Welcome to this DVD inventory program, please enter your commands." ); System.out.println( "For a list of available commands, press H." ); command = input.nextLine();
if ( command.equals( "H" ) ) { // start H if System.out.println( "H (help), provides a summary of available commands." ); System.out.println( "L (list), list the entire inventory." ); System.out.println( "I<title> (inquire), inventory info. on a specific title." ); System.out.println( "A<title> (add), add a new title to the existing inventory." ); System.out.println( "M<title> (modify), modify the want value of a specific title." ); System.out.println( "S<title> (sell), sell an item, decrease have value of that item by 1." ); System.out.println( "D (delivery), take delivery of shipment(update have values)." ); System.out.println( "O (order), write an order for additional items so have value = want value." ); System.out.println( "R (return), return extras so have value = want value." ); System.out.println( "Q (quit), quit the program." ); } // end H if
if ( command.equals( "A" ) { System.out.println( "Please enter the title that you would like to add and the want value for that item." ); newTitle = input.nextLine(); newWant = input.nextInt();
Lists are made up of nodes, a node holds a piece of information in your case it might be a specific DVD (or a DVD object!), the node also points to the next node in the list (if singly linked list) and previous node (if doubly linked list). Java has a built in list class just so you know, they are documented in the Java API.
Lists are made up of nodes, a node holds a piece of information in your case it might be a specific DVD (or a DVD object!), the node also points to the next node in the list (if singly linked list) and previous node (if doubly linked list). Java has a built in list class just so you know, they are documented in the Java API.
Wait, so how do i use this built-in class? How do i put information in the nodes once i created it?
Thanks you, that was quite helpful, although i still need more help, i ma going to write more code now, and if i encounter more problems, i will ask again.
import java.util.List; import java.util.LinkedList; import java.util.ListIterator; import java.util.Scanner; // import Scanner public class DVD {
public static void main(String[] args) { LinkedList< String > DVD = new LinkedList< String >(); Scanner input = new Scanner( System.in ); // create Scanner String command; String newTitle; int newWant; int inquire;
do { System.out.println( "Welcome to this DVD inventory program, please enter your commands." ); System.out.println( "For a list of available commands, press H." ); command = input.nextLine();
if ( command.equals( "H" ) ) { // start H if System.out.println( "H (help), provides a summary of available commands." ); System.out.println( "L (list), list the entire inventory." ); System.out.println( "I<title> (inquire), inventory info. on a specific title." ); System.out.println( "A<title> (add), add a new title to the existing inventory." ); System.out.println( "M<title> (modify), modify the want value of a specific title." ); System.out.println( "S<title> (sell), sell an item, decrease have value of that item by 1." ); System.out.println( "D (delivery), take delivery of shipment(update have values)." ); System.out.println( "O (order), write an order for additional items so have value = want value." ); System.out.println( "R (return), return extras so have value = want value." ); System.out.println( "Q (quit), quit the program." ); } // end H if
if ( command.equals( "A" ) ) { System.out.println( "Please enter the title that you would like to add and the want value for that item." ); newTitle = input.nextLine(); DVD.addLast( newTitle );
}
if ( command.equals( "I" ) ) { System.out.println( "Please enter the title position that you would like to inquire." ); inquire = input.nextInt(); DVD.get( inquire ); }
} while ( !command.equals( "Q" ) );
} // end method main
} // end class DVD
If i use A command, everything is fine and i enter a name. If i use the I part and enters "0" for the integer inquire, instead of getting what i entered in the A command, i get this message twice: Welcome to this DVD inventory program, please enter your commands. For a list of available commands, press H. Welcome to this DVD inventory program, please enter your commands. For a list of available commands, press H.
System.out.println( "Welcome to this DVD inventory program, please enter your commands." ); System.out.println( "For a list of available commands, press H." );
inside your do while loop so every time the do while executes its going to say that...
System.out.println( "Welcome to this DVD inventory program, please enter your commands." ); System.out.println( "For a list of available commands, press H." );
inside your do while loop so every time the do while executes its going to say that...
yes, but why does it say that twice? Also, i am almost done with my entire program, just need to change one more thing. And i dont' underdstand hwo to do it.
CODE
import java.util.List; import java.util.LinkedList; import java.util.ListIterator; import java.util.Scanner; // import Scanner public class DVD {
public static void main(String[] args) { LinkedList< String > DVDName = new LinkedList< String >(); LinkedList< Integer > DVDWantValue = new LinkedList< Integer >(); LinkedList< Integer > DVDHaveValue = new LinkedList< Integer >(); LinkedList< String > CustomerName = new LinkedList< String >(); LinkedList< String > CustomerAddress = new LinkedList< String >(); LinkedList< Long > CustomerPhone = new LinkedList< Long >(); Scanner input = new Scanner( System.in ); // create Scanner String command; String newTitle; int newWant; int inquire; int newHave;
do { System.out.println(); System.out.println( "Welcome to this DVD inventory program, please enter your commands." ); System.out.println( "For a list of available commands, press H." ); command = input.nextLine();
if ( command.equalsIgnoreCase( "H" ) ) { // start H if System.out.println( "H (help), provides a summary of available commands." ); System.out.println( "L (list), list the entire inventory." ); System.out.println( "I<title> (inquire), inventory info. on a specific title." ); System.out.println( "A<title> (add), add a new title to the existing inventory." ); System.out.println( "M<title> (modify), modify the want value of a specific title." ); System.out.println( "S<title> (sell), sell an item, decrease have value of that item by 1." ); System.out.println( "D (delivery), take delivery of shipment(update have values)." ); System.out.println( "O (order), write an order for additional items so have value = want value." ); System.out.println( "R (return), return extras so have value = want value." ); System.out.println( "W (wait list), check the wait list." ); System.out.println( "Q (quit), quit the program." ); } // end H if
if ( command.equalsIgnoreCase( "A" ) ) { System.out.println( "Please enter the title that you would like to add." ); newTitle = input.nextLine(); System.out.println( "Please enter the want value of the item that you would like to add." ); newWant = input.nextInt(); System.out.println( "Please enter the have value of the item that you would like to add." ); newHave = input.nextInt(); DVDName.addLast( newTitle ); DVDWantValue.addLast( newWant ); DVDHaveValue.addLast( newHave ); System.out.println( "The item " + newTitle + " and its relevant information has been added to the list." ); System.out.println( "Name: " + newTitle ); System.out.println( "Want value: " + newWant ); System.out.println( "Have value: " + newHave );
}
if ( command.equalsIgnoreCase( "S" ) ) { System.out.println( "Please enter the title position that you would like to sell." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); if ( dvdhaveValue == 0 ) { System.out.println( "We currently do not possess any more of " + dvdName + " in store." ); System.out.println( "Please place a name on the wait list." ); String personName = input.nextLine(); System.out.println( "Please enter the customer's address." ); String personAddress = input.nextLine(); System.out.println( "Please enter the customer's phone number." ); long personPhone = input.nextLong();
if ( command.equalsIgnoreCase( "I" ) ) { System.out.println( "Please enter the title position that you would like to inquire." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "Name: " + dvdName ); System.out.println( "Want value: " + dvdwantValue ); System.out.println( "Have value: " + dvdhaveValue ); }
if ( command.equalsIgnoreCase( "M" ) ) { System.out.println( "Please enter the title position of the item that you would like to change." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "Name: " + dvdName ); System.out.println( "Want value: " + dvdwantValue ); System.out.println( "Have value: " + dvdhaveValue ); System.out.println( "Please enter the new want value of the item." ); newWant = input.nextInt(); System.out.println( "Please enter the new have value of the item." ); newHave = input.nextInt(); DVDWantValue.set( inquire, newWant ); dvdwantValue = DVDWantValue.get( inquire ); DVDHaveValue.set( inquire, newHave ); dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "The new want value of " + dvdName +" is: " + dvdwantValue ); System.out.println( "The new have value of " + dvdName +" is: " + dvdhaveValue );
}
if ( command.equalsIgnoreCase( "O" ) ) { System.out.println( "Please enter the title position that you would like to order." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "Name: " + dvdName ); System.out.println( "Want value: " + dvdwantValue ); System.out.println( "Have value: " + dvdhaveValue ); if ( (dvdhaveValue == dvdwantValue) || ( dvdhaveValue >= dvdwantValue ) ) { System.out.println( "This item is not in overdemand, no need to order it!" ); } else { int orderValue = dvdwantValue - dvdhaveValue; int theoreticalHaveValue = orderValue + dvdhaveValue; System.out.println( "An purchase order for the item " + dvdName + " has been sent." ); System.out.println( "After delievery, the have value for " + dvdName + " will be: " + theoreticalHaveValue ); }
}
if ( command.equalsIgnoreCase( "D" ) ) { System.out.println( "Please enter the title position that you would like to recieve delievery on." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "Name: " + dvdName ); System.out.println( "Want value: " + dvdwantValue ); System.out.println( "Have value: " + dvdhaveValue ); if ( (dvdhaveValue == dvdwantValue) || ( dvdhaveValue >= dvdwantValue ) ) { System.out.println( "This item was not ordered!" ); } else { dvdhaveValue = dvdwantValue; DVDHaveValue.set( inquire, dvdhaveValue); System.out.println( "This item has been ordered, the new have value will be after delievery: " + dvdhaveValue ); } }
if ( command.equalsIgnoreCase( "R" ) ) { System.out.println( "Please enter the title position that you would like to return." ); inquire = input.nextInt(); String dvdName = DVDName.get( inquire ); int dvdwantValue = DVDWantValue.get( inquire ); int dvdhaveValue = DVDHaveValue.get( inquire ); System.out.println( "Name: " + dvdName ); System.out.println( "Want value: " + dvdwantValue ); System.out.println( "Have value: " + dvdhaveValue ); if ( (dvdhaveValue == dvdwantValue) || ( dvdhaveValue <= dvdwantValue ) ) { System.out.println( "We do not possess this item in excess, no need to return any of it!" ); } else { dvdhaveValue = dvdhaveValue - dvdwantValue; DVDHaveValue.set( inquire, dvdhaveValue); System.out.println( "After return, the have value for " + dvdName + " is: " + dvdhaveValue ); }
}
if ( command.equalsIgnoreCase( "L" ) ) { System.out.println( "The entire inventory is: " ); for ( String namesAgain : DVDName ) { System.out.printf( "\n%s\n", namesAgain ); } System.out.println(); }
if ( command.equalsIgnoreCase( "W" ) ); { System.out.println( "The wait list is: " ); for ( String namescustomerAgain : CustomerName ) { System.out.printf( "\n%s\n", namescustomerAgain ); } System.out.println(); }
} while ( !command.equalsIgnoreCase( "Q" ) );
} // end method main
} // end class DVD
now i need to do one more thing, i want to make it so that instead of typing in the index position of the item everytime i need it, all i have to do is type in the content of the string. ex. instead of typing "0" to get the first element, type in "Jaws" instead.
9 Oct, 2007 - 01:12 PM
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