User-defined Method

We can also create methods of our own choice to perform some task. Such methods are called user-defined methods.As we know that methods is a block of codes or set of statements which when execute it perform a particular task.

Syntax

<Access specifier> <returnType> <nameOfMethod> <(Parameter List)> {

// method body (block of codes)

}

The syntax shown above includes −

• Access specifier − It defines the access type of the method and it is optional to use.

• returnType − Method may return a value.

• nameOfMethod − This is the method name. The method signature consists of the method name and the parameter list.

• Parameter List − The list of parameters, it is the type, order, and number of parameters of a method. These are optional, method may contain zero parameters.

• method body − The method body defines what the method does with the statements.

Example

//to find minimum of two numbers

public static int minFunction(int n1, int n2) {

int min;

if (n1 > n2)

min = n2;

else

min = n1;

return min;

}

Method Calling

For using a method, it should be called.It is very simple to call a method, for calling a method we need to create object of class if method is non static otherwise simply we can call bye name.

Example

//to find minimum of two numbers

class demo

{

public int minFunction(int n1, int n2) {

int min;

if (n1 > n2)

min = n2;

else

min = n1;

return min;

}

public static void main(String [] args)

{

demo obj=new demo(); //no need of object if function will be static.

int min=obj.minFunction(20,30);

System.out.println("min="+min);

}

Actual and Formal Parameters

ways of passing parameters in Methods

1. pass by value:

In this system the value from the actual parameters are copied to the formal parameters. Hence, any changes made in the formal parameter does not reflect actual parameters. The actual parameter remains unchanged.

2. pass by reference

In this system the reference from the actual parameters are copied to the formal parameters. Hence, any changes made in the formal parameter it reflect to actual parameters.