All right I'm supposed to make a class called Stock and have an arry the size of 100. I also need to create constructors accessors and mutators. Well I've already done this part.
Now the problem is I have implement Add, Search, Delete and Update functions.
Here's my partial code: Link
First of all make you array dynamic. Instead of having an rigid array which size is immutable use a Collection...like a Set, List or Vector. These babys have dynamic size meaning that you can add and remove elements on the fly. With arrays when adding an element you have to first make a new array with the size of the old array + 1 and copy all elements from your old array to the new one and then add the new element. The same goes for deleting an element - make a new array with the size of the old array - 1 and copy the elments from the old array.
An example
Code:
import java.util.Vector;
class Element {
private String name;
public Element(String name) {
this.name=name;
}
public void setName (String name) {
this.name=name;
}
public String getName () {
return name;
}
}
class Main {
public static void main (String[] args) {
Vector v = new Vector();
for (int i = 0; i<100; i++) {
v.add(new Element("Foo"))
}
.
.
.
}
}
Removing is as easy as this
Code:
v.removeElementAt(i);
where i is the index of the element.
Updating goes like this
Code:
Element e = (Element) v.elementAt(i);
e.setName("bar");
Inserting an element
Quote:
Element e = new Element("Baz");
v.insertElementAt(i, e);
And if you still want an array representation of your collection
I've written an example app which does exactly the same things you need.
Here is the code for the array element:
Code:
public class Element {
private String name;
public Element(String name) {
this.name=name;
}
public void setName (String name) {
this.name=name;
}
public String getName () {
return name;
}
/**
* This method is invoked by JRE when there
* is a need for a String representation of
* the object (System.out.println() for example).
* You can specify here which parameters represent your object.
* The only parameter here is name.
*
* @see java.lang.Object#toString()
*/
public String toString() {
return name;
}
}
public class Main {
/** Initialize the array with 10 spaces (change it for your needs) */
private static Element[] elements = new Element[10];
/** reusable method for showing the menu (I added 2 options - Show and Quit) **/
private static void showMenu() {
System.out.println("PLEASE MAKE YOUR SELECTION(A, S, D, H or Q):" );
System.out.println("\n[A]dd new Record");
System.out.println("[S]earch Record");
System.out.println("[D]elete Record");
System.out.println("[U]pdate Record");
System.out.println("S[H]ow Records");
System.out.println("[Q]uit");
System.out.print("\n\nEnter Selection: ");
}
/** executes the program **/
private static void execute() {
try {
boolean breakOut = false;
InputStreamReader reader = new InputStreamReader(System.in);
BufferedReader input = new BufferedReader(reader);
while (!breakOut) { //loop until breakOut is true then exit
showMenu(); // after each loop we need to show the menu again
String inp = (input.readLine()).toUpperCase();
if (inp.equals("")) {
continue; //if the user entered an empty string then keep on asking
}
System.out.println("\nYou selected: " + inp);
switch(inp.charAt(0)) { //determine what the user has entered
case 'A': addRecord(); break;
case 'S': searchRecord(); break;
case 'D': deleteRecord(); break;
case 'U': updateRecord(); break;
case 'H': showRecords(); break;
case 'Q': breakOut = true; //raise the breakOut flag
default: continue; //in all other cases continue to loop
}
}
} catch (IOException e) { // if some input/output exception occured
e.printStackTrace(); //print it out and exit
}
}
/** adds a record **/
private static void addRecord () throws IOException {
String name = getUserInput ("Enter the name for the new element: ");
Element[] newArray = new Element[elements.length + 1]; //initialize a new array (old array length + 1)
for (int i = 0; i < elements.length; i++) { //add all elements from the old array
newArray[i] = elements[i];
}
newArray[newArray.length-1] = new Element(name); //add the new element to the end of the array
//array indexes start from 0 and end with length - 1
//fe. Arr[10] indexes are [0..9] not [1..10].
elements = newArray; //assign new array
}
/** searches for a record **/
private static void searchRecord () throws IOException {
String name = getUserInput ("Enter the name of the element: ");
for (int i = 0; i < elements.length; i++) {
if (elements[i].getName().equals(name)) { //if the element has the same name as entered..
System.out.println(elements[i] + " is at position " + (i+1)); //print it out (i starts from 0 therefore + 1)
return; //and exit the method
}
}
System.out.println("Could not find an element with the name " + name); //tough shit :P
}
/** deletes a record **/
private static void deleteRecord () throws IOException {
int idx;
while (true) { //ask for the index
idx = validateInput(getUserInput("Enter the index of the element: "));
if (idx > 0)
break;
}
Element[] newArray = new Element [elements.length - 1]; //create a new array (old size - 1)
int newIdx = 0; //initialize an index for the new array.
//Note that this one will not be increased when we hit the element with the index the user entered
for (int i = 0; i < elements.length; i++) { //copy all other elements
if (i != idx - 1) { //if its not the index the user entered.
//array indexes start with 0 and therefore we need to substract 1 from the number the user entered.
newArray[newIdx] = elements[i]; //just copy the element
newIdx++; //and increase the new index
}
}
elements = newArray; //assign new array
}
/** updates a record **/
private static void updateRecord () throws IOException {
int idx;
String newName;
while (true) { // get the index
idx = validateInput(getUserInput("Enter the index of the element you want to update: "));
if (idx > 0) { //and the name
newName = getUserInput("Enter new name for the element: ");
break;
}
}
Element e = elements[idx-1]; //get the element from the array (-1 again from the user input)
e.setName(newName); // update the name
}
/** prints out the records **/
private static void showRecords() {
for (int i = 0; i < elements.length; i++) {
System.out.println((i+1) + "-" + elements[i]); //i+1 because i starts from 0. Uses the toString method from the Element class
}
}
/** reusable method for validating user input and convert it to int**/
private static int validateInput(String input) {
int ret = -1; // -1 represents invalid input
if (!input.equals("")) {
try {
ret = Integer.parseInt(input); //try to parse the input into int
if ((ret - 1) < 0 || (ret - 1) >= elements.length) { //check if the number is between the array capacity
System.out.println ("Index must be between 1 and " + elements.length + "!");
ret = -1;
}
} catch (NumberFormatException nfe) { //if parsing failed
System.out.println ("Not an integer: " + input);
}
}
return ret;
}
/** reusable method for getting user input **/
private static String getUserInput(String displayString) throws IOException {
String ret = null;
InputStreamReader reader = new InputStreamReader(System.in);
BufferedReader input = new BufferedReader(reader);
while (true) { //infinite loop
System.out.print (displayString);
ret = input.readLine();
if (!ret.equals("")) //if the user enters an empty string then ask again
break; //break out the infinite loop
}
return ret;
}
public static void main(String args[]) {
for (int i = 0; i < elements.length; i++)
elements[i] = new Element("Foo" +( i + 1));
execute();
}
}
It took me about half an hour and I also included comments because I do not know your current skill with Java.
have fun, and copy/paste this code and you should be just fine
Just analyse the code, try to decompose it and try understand what some piece of code does and then...if you really want to be a Java guru ... expand this logic. For example create methods for sorting the array and for swapping element positions etc.
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Had to use quote tags after using code tag for 3 times 
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