Suggestion on how to improve the program

[crowledg]

/**A Program for a supermarket running a loyalty card scheme.Hard code 5 gifts that the supermarket offer and the points the gifts cost.
 *Hard code the users for the system. Each will have a pin and points stored in the array.
 *Be a menu with options to View Gifts, Buy Gifts, Add points and Exit. The menu should loop until the user chooses to Exit.
 *When the user buys a gift the amount of points the gift cost must be deducted from the users points.
 *When the user buy gifts the amount of points must be added on to the user points.
 *Valadations must be done.
 * @(#)project2.java
 *
 *
 * @author
 * @version 1.00 2013/3/16
 */

import java.util.Scanner;
public class project2 {

    public static void main (String args[]) {

    	Scanner input = new Scanner (System.in);

    	//declare variables
    	int giftids[]={1,2,3,4,5};
    	int giftpoints[]={2000,1200,700,200,1000};
    	String gifts[]={"i-pad","PS3","Bike","i-pod","Laptop"};
    	int customerpoints[]={500,1200,300};
    	String names[]={"James","Joe","Danny"};
    	int pin[]={111,222,333};
    	int choices=0, sub=0, userpin=0, usergiftids=0, additional_points=0;
    	boolean flag=false;
    	String strlogin, strpin, stroption, strgift, strusergiftids, stradditional_points;

    	//Print out welcome screen
    	System.out.print("\n---Welcome to the Loyalty Card Scheme  ---");
    	System.out.print("\n\nPlease choose an option : \n\n1: Login \n2: Exit\n-->");
    	strlogin=input.next();

    	//while loop to check that only 1 or 2 is entered
    	while(!strlogin.matches("[1-2]")){
    		//beep to alert user that they have made an error
    		java.awt.Toolkit.getDefaultToolkit().beep();
    		System.out.println("\nError! 1 or 2 only");
    		System.out.print("\n\nPlease choose an option : \n\n1: Login \n2: Exit\n-->");
    		strlogin=input.next();
    	}//end while loop to check to only 1 or 2 is entered

    	choices=Integer.parseInt(strlogin);

    	//do loop to makes sure that the choices are excuted at least once
    	do{
    		//if statement to check if 1 is entered
    		if(choices==1){
    			System.out.print("\nPlease enter Pin: ");
    			//take in pin from user
    			strpin=input.next();
    			// loop to check that only correct pin is entered
    			while(!strpin.matches("\\d+")){
    				//beep to alert user that they have made an error
    				java.awt.Toolkit.getDefaultToolkit().beep();
    				System.out.println("Incorrect Pin!");
    				System.out.print("\nPlease enter Pin: ");
    				strpin=input.next();
    			}//end while loop to check only correct pin is entered
    			userpin=Integer.parseInt(strpin);
    		}//end if choices ==1

    		//else statment to exit program
    		else{
    			System.out.println("\n\n\t***Thank you for using the Loyalty Card Scheme***");
    			System.out.print("\n\n");
    			System.exit(0);
    		}//end else to exit program

    		//for loop to go through the array to look for user pin
    		for(int i=0; i<pin.length; i++){
    			//if statemenr if the pin enter is in the array
    			if(userpin == pin[i]){
    				//change flag to true
    				flag=true;
    				//holds onto the value of i
    				sub=i;
    				//jump out of loop
    				break;
    			}//end if userpin is true
    		}//end for loop

    		//if flag is flase
    		if(flag==false){
    			//beep to alert user that they have made an error
    			java.awt.Toolkit.getDefaultToolkit().beep();
    			System.out.println("Incorrect Pin!");
    		}//end if flag is false

    		}while(flag ==false);

    		stroption="";

    		//loop to print out user's name and points and the option menu
    		while(!stroption.equals("4")){
    			System.out.println("\nWelcome: " + names[sub]);
    			System.out.println("Points : "+ customerpoints[sub]);
    			//print out option menu
    			System.out.print("\n\nPlease choose an option : \n\n1: View Gifts \n2: Buy Gifts \n3: Add Points \n4: Exit\n-->");
    			//take in the option the user chooses
    			stroption=input.next();

    			//check that only 1 to 4 is entered
    			while(!stroption.matches("[1-4]")){
    				//beep to alert user that they have made an error
    				java.awt.Toolkit.getDefaultToolkit().beep();
    				System.out.println("\nError! 1 to 4 only");
    				System.out.print("\n\nPlease choose an option : \n\n1: View Gifts \n2: Buy Gifts \n3: Add Points \n4: Exit\n-->");
    				stroption=input.next();
    			}//end while to check only 1 to 4 is entered

    			choices=Integer.parseInt(stroption);

    			//if statements if the user selects 1
    			if(choices==1){
    				//print out heading for table
    				System.out.println("\n\tId \t Gift \t\t Gift Points:");
    				System.out.println("\t------------------------------------");
    				//for loop to print out gifts in table
    				for (int i = 0; i < gifts.length; i++){
    					System.out.println("\t"+giftids[i] + "\t" + gifts[i] + "\t\t\t" + giftpoints[i]);
    				}//end for loop
    			}//end if choices ==1

    			//else if statement if the user choose's option 2
    			else if(choices==2){
    				System.out.print("\nEnter gift Id that you wish to purchase? \n-->");
    				//take in the id of the gift that the user wishes to purchase
    				strusergiftids=input.next();

    				//check that only 1 to 5 can be entered
    				while(!strusergiftids.matches("[1-5]")){
    					java.awt.Toolkit.getDefaultToolkit().beep();
    					System.out.println("Incorrect Gift ID!");
    					System.out.print("\nEnter gift Id that you wish to purchase? \n-->");
    					strusergiftids=input.next();
    				}//end while cheeck 1 to 5 only
    				usergiftids=Integer.parseInt(strusergiftids);

					//for loop  to go through the gift ids
    				for(int x=0; x<giftids.length; x++){

    					//while loop to check to the gift id corresponds to the id the user inputted
    					while(usergiftids == giftids[x]){

    						//if statment if the customers points are less than the points needed to buy the gift
    						if(customerpoints[sub]<giftpoints[x]){
    							//beep to alert user that they have made an error
    							java.awt.Toolkit.getDefaultToolkit().beep();
    							System.out.println("\t***** "+gifts[x]+" "+giftpoints[x]+" Points *****");
    							//Print out if not got enough points
    							System.out.println("\n\t**** Not enough points ****");
    							break;
    						}//end if customers points are less that points needed for the gift

							//else statement if the points are greater than the cost of the gift
    						else{
    							System.out.println("\t***** "+gifts[x]+" "+giftpoints[x]+" Points *****");
    							//Print out if the user has enough points
    							System.out.println("\n\t***** " + gifts[x] +" Purchased *****");
    							//take the cost of the gift from the user points
    							customerpoints[sub]=customerpoints[sub]-giftpoints[x];
    							//break out of the loop
    							break;
    						}//end else customer has enough points to buy the gift
    					}//end while usergiftid == gift ids
    				}//end for
    			}//end if else choice == 2

    			//else if statement if user enters choice 3
    			else if(choices==3){
    				System.out.print("\nHow many Points do you want to buy? \n-->");
    				//take in how many points the user wants to add
    				stradditional_points=input.next();

    				//check that only numbers can be entered
    				while(!stradditional_points.matches("\\d+")){
    					//beep to alert user that they have made an error
    					java.awt.Toolkit.getDefaultToolkit().beep();
    					System.out.println("Numbers only!");
    					System.out.print("\nHow many Points do you want to buy? \n--> ");
    					stradditional_points=input.next();
    				}//end check that only numbers can be entered
    				additional_points=Integer.parseInt(stradditional_points);
    				//add the points onto the customers existing balance
    				customerpoints[sub] = customerpoints[sub]+additional_points;
    			}//end if else choice ==3

    			//else statement to end the program
    			else{
    				System.out.println("\n\n\t***Thank you for using the Loyalty Card Scheme***");
    				//Get the program to jump down 2 lines
    				System.out.print("\n\n");
    				System.exit(0);
    			}//end else to exit program
    	}//end while stroption

    }//end main method

}//end class

[wsaryada]

The first thing I can suggest is to refactor your code into smaller methods. It so hard to maintain a code where you have such a big method. The whole body of a method should be seen without scrolling the page.

[Junky]

I agree!

Not only is all your code inside the main method about 90% of it is inside a single loop. You need to break your code down into smaller chunks which can be placed into methods. You can then call those methods as many times as you need.