1. Introduction to programming in java
Lecture 06
Input from keyboard

2. Introduction
Picture taken from Book entitled Introduction to Programming in Java: An interdisciplinary approach

3. Introduction
Picture taken from Book entitled Introduction to Programming in Java: An interdisciplinary approach

4. Input From Keyboard Java supports three standard input/output streams:
System.in (standard input device),
System.out (standard output device), and System.err (standard error device).
The System.in is defaulted to be the keyboard; while System.out and System.err are defaulted to the console.

5. Input From Keyboard double i = scanner.nextDouble();
Java SE 5 introduced a new class called Scanner in package java.util to simplify formatted input.
Instantiate a Scanner
Scanner myScanner = new Scanner(System.in);
Read an entire line of text we use nextLine();
String input = myScanner.nextLine();
Read an integer value we use nextInt()
int i = scanner.nextInt();
Read floating valueinteger value we use nextDouble()
double i = scanner.nextDouble();

6. Example # 1: Enter your name
import java.util.Scanner; public class MyName { public static void main(String[] args) { Scanner in = new Scanner(System.in); System.out.print("Enter your full name: "); String name = in.nextLine(); System.out.println(“Wellcome Mr. " + name); }

7. Example 2: Get Student ID
import java.util.Scanner;
public class StudentID {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.print("Enter your student ID : ");
int id = in.nextInt();
System.out.println(“Your ID : " + id); }

8. Example 3: Product of 2 numbers
import java.util.Scanner;
public class Product {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.print("Enter first number : ");
double x = in.nextDouble(); System.out.print("Enter second number : ");
double y = in.nextDouble();
double ans = x * y ;
System.out.println( x + “ * “ + y + “ = " + ans); }

9. Example 3: Name and Age import java.util.*; public class NameAndAge {
public static void main(String[] args) {
int age;
String name;
Scanner in = new Scanner(System.in);
System.out.println("Enter full name: ");
name = in.nextLine();
System.out.println("How old are you? ");
age = in. nextInt();
System.out.println(name + '\t' + age); }

10. Practice Questions
Write a program called MyMath which first reads two integer values from the standard input and then compute sum , product, division and subtract of those two numbers and prints the result. For example
> Java MyMath
Enter 1st number: 10
Enter 2nd number: 5
Sum : = 15
Minus: 10-5 = 5
Product: 10 * 5 = 50
Division: 10 / 5 = 2

11. Submission deadline of Assignment No. 1 is 24th Sep 2013
For details: See Lecture 05