C# 0 The Complete Reference

Console.Out

 and 

Console.Error

. By 

default, both write to the console.

// Write to Console.Out and Console.Error.

using System;

class ErrOut {

  static void Main() {

    int a=10, b=0;

    int result;

    Console.Out.WriteLine("This will generate an exception.");

    try {

      result = a / b; // generate an exception

    } catch(DivideByZeroException exc) {

      Console.Error.WriteLine(exc.Message);

    }

  }

}

The output from the program is shown here:

This will generate an exception.

Attempted to divide by zero.

Sometimes newcomers to programming are confused about when to use 

Console.Error

.

Since both 

Console.Out

 and 

Console.Error

 default to writing their output to the console, 

why are there two different streams? The answer lies in the fact that the standard streams 

can be redirected to other devices. For example, 

Console.Error

 can be redirected to write to 

a disk file, rather than the screen. Thus, it is possible to direct error output to a log file, for 

example, without affecting console output. Conversely, if console output is redirected and 

error output is not, then error messages will appear on the console, where they can be seen. 

We will examine redirection later, after file I/O has been described.