Question

I have a college assignment where I need to print out items sold by a hardware store, take input from a user, perform some calculations on that input, and then print out an invoice.

I have been able to successfully print out the items sold by the hardware store, but am encountering problems with the while loop that takes the input.

The program asks the user to enter a CODE and then asks for the corresponding QUANTITY. This works fine on the first iteration of the loop, but on the second iteration the user prompts for “CODE:” and “QUANTITY:” appear on the same line, despite my use of println when prompting the user.

I would greatly appreciate a detailed response appropriate for someone new in programming.

Here’s the code:

 import java.util.Scanner;

 class HardwareStore {


    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);


        System.out.println("WELCOME TO THE HARDWARE STORE!");
        System.out.println("----------------------------------------------------------------------");


        String sticky = "G22";
        String keyring = "K13";
        String screwy = "S21";
        String padlock = "I30";


        int stickyprice = 10989;
        int keyringprice = 5655;
        int screwyprice = 1099;
        int padlockprice = 4005;


        System.out.println("CODE\t\tDESCRIPTION\t\t\t\t\tPRICE");
        System.out.println("----\t\t-----------\t\t\t\t\t-----");

        System.out.println(sticky + "\t\tSTICKY Construction Glue, Heavy Duty, \n\t\t7oz, 12 Pack \t\t\t\t\t$" + stickyprice);
        System.out.println(keyring + "\t\tCAR-LO Key Ring, Quick Release, \n\t\t1 Pack\t\t\t\t\t\t$ " + keyringprice);
        System.out.println(screwy + "\t\t!GREAT DEAL! SCREW-DUP Screwy Screws, \n\t\tDry Wall Screws, 3 in. Long, 50 Pack\t\t$ " + screwyprice);
        System.out.println(padlock + "\t\tLET-IT-RAIN, Weather Proof Padlock, \n\t\tPortable, One Push Functionality\t\t$ " + padlockprice);
        System.out.println("----------------------------------------------------------------------");


        int i = 10000; 
        String [] usercode = new String[i]; 
        int [] userquantity = new int[i];


        System.out.println("PLEASE ENTER YOUR ORDER:");


        while (true) {
            System.out.println("CODE: (X to terminate)");
            usercode[i] = in.nextLine();

            if (usercode[i].equalsIgnoreCase("x")) {
                break;
            }

            System.out.println("QUANTITY: ");
            userquantity[i] = in.nextInt();
        } 
    }
}

Answer 1

when you enter the QUANTITY you’re pressing enter. That newline character isn’t used by in.nextInt();, it remains in the scanner buffer, until you roll around to in.nextLine() again.

At that point in.nextLine() reads until it finds a newline character, which just happens to be the next one in the buffer. So it skips straight to QUANTITY again.