Variable is a basic concept of C#. Variable is a computer memory location that is reserved for storing the data used by the program or application. Each variable is given a name, assigned a value and type of value by a programmer. By the help of variable value may be read and change.
Variable must be declared as a particular type such as integer, a character or a string. Variable type can not be change but value can casted in another type. This concept is known as casting. The following example declares an integer variable:
Initialize a variable using the assignment operator (=)
int rate = 10;
New value given to variable as a requirement:
int rate = 10; // old value
int rate = 24; // assign new value
A constant is similar to a variable in that it provides a named location in memory to store a data value. Constants differ in one significant way in that once a value has been assigned to a constant it can not subsequent be changed.
Constants are particularly useful if there is a value which is used repeatedly throughout the application code. Rather then use the value each time. It makes the code easier to read if the value is first assignment to a constant which is then referred in the code.
Constant must be initialized at the same time that they are declared and must be prefixed with the
Const int rate = 10;