Information Technology Reference
In-Depth Information
Table 2-1.
The SimpleProgram Program, Line by Line
Line Number
Description
Tells the compiler that this program uses types from the
System
namespace.
Line 1
Declares a new namespace, called
Simple
.
Line 3
The new namespace starts at the open curly brace on line 4 and
extends through the matching curly brace on line 12.
Any types declared within this section are members of the
namespace.
Line 5
Declares a new class type, called
App
.
Any members declared between the matching curly braces on
lines 6 and 11 are members that make up this class.
Declares a method called
Main
as a member of class
App
.
In this program,
Main
is the only member of the
App
class.
Main
is a special function used by the compiler as the starting
point of the program.
Line 7
Line 9
Contains only a single, simple statement; this line constitutes the
body of
Main
.
Simple statements are terminated by a semicolon.
This statement uses a class called
Console
, in namespace
System
, to print out the message to a window on the screen.
W thout the
using
statement in line 1, the compiler wouldn't
have known where to look for class
Console
.
More About SimpleProgram
A C# program consists of one or more type declarations. Much of this topic is spent explaining
the different types that you can create and use in your programs. The types in a program can
be declared in any order. In the
SimpleProgram
example, only the
class
type is declared.
A
namespace
is a set of type declarations associated with a name.
SimpleProgram
creates a
new namespace called
Simple
, and uses a predefined namespace called
System
.
To compile the program, you can use Visual Studio or the command-line compiler. To use
the command-line compiler, use the following command:
csc SimpleProgram.cs
In this command,
csc
is the name of the command-line compiler and
SimpleProgram.cs
is
the name of the source file.
