Reading from the Keyboard

• Below is a code example that demonstrates getting character input.

  Character-based Input (Applications only)

  import java.io.*;
  
  /**
   *  ReadIn is an application to demonstrate reading input.
   *
   *  @author Your Name
   */
  
  public class ReadIn
  {
  public static void main (String args[]) throws IOException
  {
  
      BufferedReader keyboard =
           new BufferedReader(new InputStreamReader(System.in));
  
      String  str = "";
      int num1;
      int num2;
  
      System.out.print("Enter a number: ");
      str = keyboard.readLine();
      num1 = Integer.parseInt(str);
      str = keyboard.readLine();
      num2 = Integer.parseInt(str);
      System.out.println(num1 + " + " + num2 + " is " + (num1 + num2));
  }
  }
  

• Note that there's a new package to import for I/O.
• For our applications that get input, make sure to add the throws IOException to the end of main's signature.
• This code indicates that our program will ignore any errors.
• This is not the best way to write code, but we will keep it simple for now. A more proper way to handle errors is though exception handling; we may get to this topic later.
• Note that we declare an object called keyboard that is of class BufferedReader, and create the memory for the keyboard object by calling the constructor for the BufferedReader class.
• The keyboard object will be used to get input from the standard place (System.in).
• The assignment statement uses dot-notation to call the method readLine(), which reads in one line of data from the keyboard.
• The end of the line, and therefore the end of the data, occurs when the user presses the Enter key.
• The value entered is stored in the the string object str.