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Answer:

Yes. It is an ordinary text file. On Unix, use the cat command. Or use any text editor.


print() and println()

import java.io.*;

class PrintSquare
{

  public static void main ( String[] args )  throws IOException
  {
    File file = new File( "mySquare.txt" );
    PrintWriter  output = new PrintWriter( file );

    double x = 1.7320508;

    output.println( "The square of " + x + " is " + x*x );  

    output.close();
  }
}

The print(String s) method of PrintWriter sends the characters from the String to the output stream. No line separator characters are sent after them. The println(String s) method sends the same characters followed by line separator characters.

Both methods can be used to output numerical results as characters just as we have been doing with System.out.println(). The following

"The square of " + x + " is " + x*x

creates one long string by converting x and x*x to character form and then appending those characters to the string literals. It is this final long string that is the argument to println().

Here is a run of the program:

C:\temp> javac PrintSquare.java
C:\temp> java PrintSquare
C:\temp> type mySquare.txt
The square of 1.7320508 is 2.9999999737806395

The program does not send any output to the command window. To see the output of the program look at the file it creates.


QUESTION 13:

Could the name of the output file come from user input?