using System;
class ReferenceAndOutputParameters
{
public void aMethod()
{
int y = 5;
int z;
Console.WriteLine( "Original value of y: {0}", y );
Console.WriteLine( "Original value of z: uninitialized
" );
SquareRef( ref y );
SquareOut( out z );
Console.WriteLine( "Value of y after SquareRef: {0}", y );
Console.WriteLine( "Value of z after SquareOut: {0}
", z );
Square( y );
Square( z );
Console.WriteLine( "Value of y after Square: {0}", y );
Console.WriteLine( "Value of z after Square: {0}", z );
}
void SquareRef( ref int x )
{
x = x * x;
}
void SquareOut( out int x )
{
x = 6;
x = x * x;
}
void Square( int x )
{
x = x * x;
}
}
class ReferenceAndOutputParamtersTest
{
static void Main( string[] args )
{
ReferenceAndOutputParameters test = new ReferenceAndOutputParameters();
test.aMethod();
}
}
Language Basics
Preprocessor 2
/*
C# Programming Tips & Techniques
by Charles Wright, Kris Jamsa
Publisher: Osborne/McGraw-Hill (December 28, 2001)
ISBN: 0072193794
*/
namespace nsPreProc
{
using System;
public class PreProc
{
static public void Main()
{
#if ALTMAIN
#warning Compiling alternate statement
Console.WriteLine ("Using alternate Main()");
#elif OTHERMAIN
#warning Compiling other statement
Console.WriteLine ("Using other Main()");
#else
#warning Compiling main
Console.WriteLine ("Using Main()");
#endif
}
#line 200
#if SHOWERROR
int iVar;
#error This is line 23 but the error report should show line 202
#endif
}
}
Demonstrate #elif
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Demonstrate #elif.
#define RELEASE
using System;
public class Test5 {
public static void Main() {
#if EXPERIMENTAL
Console.WriteLine("Compiled for experimental version.");
#elif RELEASE
Console.WriteLine("Compiled for release.");
#else
Console.WriteLine("Compiled for internal testing.");
#endif
#if TRIAL && !RELEASE
Console.WriteLine("Trial version.");
#endif
Console.WriteLine("This is in all versions.");
}
}
Demonstrate #else
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Demonstrate #else.
#define EXPERIMENTAL
using System;
public class Test4 {
public static void Main() {
#if EXPERIMENTAL
Console.WriteLine("Compiled for experimental version.");
#else
Console.WriteLine("Compiled for release.");
#endif
#if EXPERIMENTAL && TRIAL
Console.Error.WriteLine("Testing experimental trial version.");
#else
Console.Error.WriteLine("Not experimental trial version.");
#endif
Console.WriteLine("This is in all versions.");
}
}
Use a symbol expression
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Use a symbol expression.
#define EXPERIMENTAL
#define TRIAL
using System;
public class Test2 {
public static void Main() {
#if EXPERIMENTAL
Console.WriteLine("Compiled for experimental version.");
#endif
#if EXPERIMENTAL && TRIAL
Console.Error.WriteLine("Testing experimental trial version.");
#endif
Console.WriteLine("This is in all versions.");
}
}
Demonstrate #if, #endif, and #define
/*
C#: The Complete Reference
by Herbert Schildt
Publisher: Osborne/McGraw-Hill (March 8, 2002)
ISBN: 0072134852
*/
// Demonstrate #if, #endif, and #define.
#define EXPERIMENTAL
using System;
public class Test1 {
public static void Main() {
#if EXPERIMENTAL
Console.WriteLine("Compiled for experimental version.");
#endif
Console.WriteLine("This is in all versions.");
}
}
#undef, #elif, and #else preprocessor directives
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example4_17.cs illustrates the use of the
#undef, #elif, and #else preprocessor directives
*/
#define DEBUG
#undef DEBUG
#define PRODUCTION
public class Example4_17
{
public static void Main()
{
int total = 0;
int counter = 0;
myLabel:
counter++;
total += counter;
System.Console.WriteLine(“counter = ” + counter);
if (counter < 5)
{
#if DEBUG
System.Console.WriteLine("goto myLabel");
#elif PRODUCTION
System.Console.WriteLine("counter < 5");
#else
System.Console.WriteLine("goto myLabel, counter < 5");
#endif
goto myLabel;
}
System.Console.WriteLine("total = " + total);
}
}
[/csharp]