Книга: C# 2008 Programmer
Variables
Variables
In C#, you declare variables using the following format:
datatype identifier;
The following example declares and uses four variables:
class Program {
static void Main(string[] args) {
//---declare the variables---
int num1;
int num2 = 5;
float num3, num4;
//---assign values to the variables---
num1 = 4;
num3 = num4 = 6.2f;
//---print out the values of the variables---
Console.WriteLine("{0} {1} {2} {3}", num1, num2, num3, num4);
Console.ReadLine();
return;
}
}
Note the following:
? num1
is declared as an int
(integer).
? num2
is declared as an int
and assigned a value at the same time.
? num3
and num4
are declared as float
(floating point number)
? You need to declare a variable before you can use it. If not, C3 compiler will flag that as an error.
? You can assign multiple variables in the same statement, as is shown in the assignment of num3
and num4
.
This example will print out the following output:
4 5 6.2 6.2
The following declaration is also allowed:
//---declares both num5 and num6 to be float
// and assigns 3.4 to num5---
float num5 = 3.4f, num6;
But this one is not allowed:
//---cannot mix different types in a declaration statement---
int num7, float num8;
The name of the variable cannot be one of the C# keywords. If you absolutely must use one of the keywords as a variable name, you need to prefix it with the @ character, as the following example shows:
int @new = 4;
Console.WriteLine(@new);
- Using Double Quotes to Resolve Variables in Strings with Embedded Spaces
- Using Environment Variables
- Perl Variables and Data Structures
- Special Variables
- Class and Object Variables
- Creating Your Own Variables
- Using Variables in Shell Scripts
- Built-In Variables
- Using Single Quotes to Maintain Unexpanded Variables
- 3.1.10 Static Variables
- 3.1.11 External Variables
- 3.1.12 Volatile Variables