A method is a group of statements that together perform a task. Every C# program has at least one class with a method named Main.To use a method, you need to:
1.Call the method 2.Call MethodWhen you define a method, you basically declare the elements of its structure. The syntax for defining a method in C# is as follows:
<Access
Specifier>
<Return
Type>
<Method
Name>(Parameter List)
{
Method Body
}
Following are the various elements of a method:
Access Specifier:This determines the visibility of a variable or a method from another class. Return type:A method may return a value. The return type is the data type of the value the method returns. If the method is not returning any values, then the return type is void. Method name:Method name is a unique identifier and it is case sensitive. It cannot be same as any other identifier declared in the class. Parameter list: Enclosed between parentheses, the parameters are used to pass and receive data from a method. The parameter list refers to the type, order, and number of the parameters of a method. Parameters are optional; that is, a method may contain no parameters. Method body:This contains the set of instructions needed to complete the required activity.
Following code snippet shows a function FindMaxthat takes two integer values and returns the larger of the two. It has public access specifier, so it can be accessed from outside the class using an instance of the class.
class
NumberManipulator
{
public
int
FindMax(int num1,
int num2)
{
/* local variable
declaration */
int result;
if
(num1
> num2)
result
= num1;
else
result
= num2;
return result;
}
...
}
You can call a method using the name of the
method. The following example illustrates this:
using
System;
namespace
CalculatorApplication
{
class
NumberManipulator
{
public
int
FindMax(int num1,
int num2)
{
/* local variable
declaration */
int result;
if
(num1
> num2)
result
= num1;
else
result
= num2;
return result;
}
static
void
Main(string[] args)
{
/* local variable
definition */
int a
=
100;
int b
=
200;
int ret;
NumberManipulator n
=
new
NumberManipulator();
//calling the FindMax
method
ret
= n.FindMax(a, b);
Console.WriteLine("Max value is : {0}", ret
);
Console.ReadLine();
}
}
When the above code is compiled and executed, it produces the following result:
Max value is : 200
You can also call public method from other classes by using the instance of the class. For example, the method 'FindMax' belongs to the 'NumberManipulator class', you can call it from another class Test.
using
System;
namespace
CalculatorApplication
{
class
NumberManipulator
{
public
int
FindMax(int num1,
int num2)
{
/* local variable declaration */
int result;
if
(num1
> num2)
result
= num1;
else
result
= num2;
return result;
}
}
class
Test
{
static
void
Main(string[] args)
{
/* local variable definition */
int a
=
100;
int b
=
200;
int ret;
NumberManipulator n
=
new
NumberManipulator();
//calling the FindMax method
ret
= n.FindMax(a, b);
Console.WriteLine("Max value is : {0}", ret
);
Console.ReadLine();
}
}
}
When the above code is compiled and executed,
it produces the following result:
Max value is : 200
A method can call itself. This is known as recursion. Following is an example that calculates factorial for a given number using a recursive function:
using
System;
namespace
CalculatorApplication
{
class
NumberManipulator
{
public
int factorial(int num)
{
/* local variable declaration */
int result;
if
(num
==
1)
{
return
1;
}
else
{
result
= factorial(num
-
1)
* num;
return result;
}
}
static
void
Main(string[] args)
{
NumberManipulator n
=
new
NumberManipulator();
//calling the factorial method
Console.WriteLine("Factorial of 6 is : {0}", n.factorial(6));
Console.WriteLine("Factorial of 7 is : {0}", n.factorial(7));
Console.WriteLine("Factorial of 8 is : {0}", n.factorial(8));
Console.ReadLine();
}
}
}
When the above code is compiled and executed, it produces the following result:
Factorial of 6 is: 720
Factorial of 7 is: 5040
Factorial of 8 is: 40320
Passing Parameters to a
Method
When method with parameters is called, you need to pass the parameters to the method. In C#, there are three ways that parameters can be passed to a method:
|
Mechanism |
Description |
|
This method copies the actual
value of an argument into the formal parameter of the function. In this case,
changes made to the parameter inside the function have no effect on the
argument. |
|
|
This method copies the reference
to the memory location of an argument into the formal parameter. This means that
changes made to the parameter affect the argument. |
|
|
TThis method helps in returning
more than one value. |