Question

As I’m extremely new to java, I seem to have trouble grasping some concepts. Here is a program. I understand the System.out part reasonably well but am having trouble getting my head around how the input works.

// IO Example:

import java.util.Scanner;

public class HelloAge {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("What's your name? ");
        String name = in.nextLine();
        System.out.print("In which year were you born? ");
        Integer birthyear = in.nextInt();
        Integer age = 2011 - birthyear;
        System.out.println("Hello, " + name + "!  Welcome to COMP1100.\n" +
                           "You will turn " + age + " this year.");
    }
}

I can’t see why there is in.nextLine(); and then in.nextInt(); I don’t see what those two commands have in common or what they’re supposed to mean? That’s my main issue.

Answer 1

In general try the javadocs first; in this case the Scanner docs.

First create a new scanner for reading stdin…

Scanner in = new Scanner(System.in);

Read in the entire next line which is all chars up to the next newline…

String name = in.nextLine();

Read the next set of chars as an integer…

Integer birthyear = in.nextInt();