Numeric Input

The same method is used for numeric input using a redirected input file. The program is written to do numeric input from the keyboard, then connected to a data file by redirection. Here is a program that adds up two integers entered from the keyboard:

import java.io.*;
class AddTwo
{
  public static void main ( String[] args ) throws IOException
  {
    int numberA, numberB;

    String line;
    BufferedReader stdin = new BufferedReader( 
        new InputStreamReader( System.in ) );

    System.out.println("Enter first number:");
    line      = stdin.readLine();
    numberA   = Integer.parseInt( line );

    System.out.println("Enter second number:");
    line      = stdin.readLine();
    numberB   = Integer.parseInt( line );

    System.out.println( "Sum: " + (numberA + numberB) );
  }
}

Here is its normal operation:

C:\users\default\JavaLessons>java AddTwo

Enter first number:
12
Enter second number:
7
Sum: 19

C:\users\default\JavaLessons>