1.7.1. C# variable definition #

C# syntax for variable definition

<data_type> <variable_list>;

Here, data_type must be a valid C# data type, which can be char 、 int 、 float 、 double or other user-defined data types. variable_list can consist of one or more identifier names separated by commas.

Some valid variable definitions are as follows:

int i, j, k;
char c, ch;
float f, salary;
double d;

You can initialize when a variable is defined:

int i = 100;

1.7.2. C# variable initialization #

Variables are initialized (assigned) by an equal sign followed by a constant expression. The general form of initialization is:

variable_name = value;

Variables can be initialized when declared (specify an initial value). Initialization consists of an equal sign followed by a constant expression, as follows:

<data_type> <variable_name> = value;

Some examples:

int d = 3, f = 5;    /* Initialize d and f. */
byte z = 22;         /* Initialize z. */
double pi = 3.14159; /* Declare the approximate value of pi */
char x = 'x';        /* The value of variable x is 'x' */

Initializing variables correctly is a good programming habit, otherwise sometimes the program will produce unexpected results.

Take a look at the following example, using various types of variables:

namespace VariableDefinition
{
    class Program
    {
        static void Main(string[] args)
        {
            short a;
            int b ;
            double c;
            /* Actual initialization */
            a = 10;
            b = 20;
            c = a + b;
            Console.WriteLine("a = {0}, b = {1}, c = {2}", a, b, c);
            Console.ReadLine();
        }
    }
}

a = 10, b = 20, c = 30

1.7.3. Accept values from users #

System in the namespace Console class provides a function ReadLine() to receive input from the user and store it in a variable.