Method in java
When
we define a set of code within a block having a name is called method. It can
call or invoke at any time.
We can define the Java method as
follows
A simple Java method requires
a minimum of three items:
Access
Level : public, private, protected
Return
Type : void, int, double, (etc.)
Name : whatever you want to call
the method
Simple example of a function
private double
simpleInterest(double p, double t, double r)
{
double si=(p*t*r)/100;
return si;
}
Here access specifier is
private, return type double and the function name is simpleInterst with three
parameters. In Java convention function start with a small character.
Access Specifier
The access modifier or Access specifier is the access type of the method/Function. It specifies the visibility or accessibility of the method. Java has four types of access specifier or access modifier:
- Default: Java uses default access specifier by default. It is visible only from the same package only.
- Public: The method is accessible (visible in) by all classes when we use public specifier in Java application.
- Private: When we use a private access specifier, the method is accessible only in the classes in which it is defined.
- Protected: Protected access specifier when use, the method is accessible within the same package or subclasses in a different package.
A full example of a function
public class Function1
{
int a,b,c;
int Add() // return method
{
a=10;
b=30;
c=a+b;
return c;
}
public static void main(String smart[])
{
int x;
Function1 ob=new Function1();
x=ob.Add();
System.out.println("Sum="+x);
}
}
What is the Actual parameter?
Ans: The actual parameter is
a parameter as appear in a method/function. Actual parameters (also known
as arguments) are what is passed by the caller.
What is a Formal parameter?
Ans: the Identifier used in a method to stand for the
value that is passed into the method by a caller. Formal parameters are also known as parameters of the function.
Simple Interest in Java
import java.util.*;public class SimpleInterest
{
double p, t, r, si, amount; // Instance Variable
void inputValue()
{
Scanner sc=new Scanner(System.in);
System.out.println("Enter Principal, Time and Rate :");
p=sc.nextDouble();
t=sc.nextDouble();
r=sc.nextDouble();
}
void simpleInt()
{
si=(p*t*r)/100.0;
amount=p+si;
}
void display()
{
System.out.println("Simple Interest="+si);
System.out.println("Amount="+amount);
}
public static void main()
{
SimpleInterest ob=new SimpleInterest();
ob.inputValue();
ob.simpleInt();
ob.display();
}
}
Prime Number in Java with Method
import java.util.*;
public class PrimeNumber
{
int n, i;
boolean p;
boolean prime(int x)
{
n=x;
p=true;
for(i=2;i<n;i++)
{
if(n%i==0)
{
p=false;
break;
}
}
return p;
}
public static void main()
{
int n; // Local variable
boolean pr;
Scanner sc=new Scanner(System.in);
PrimeNumber ob=new PrimeNumber();
System.out.println("Enter number:");
n=sc.nextInt();
pr=ob.prime(n);
if(pr==true)
System.out.println("Prime Number");
else
System.out.println("Not Prime Number");
}
}
Power and Factorial Method with return and Decimal Format
import java.io.*;
import java.math.RoundingMode;
import java.text.DecimalFormat;
public class SeriesPowFact
{
//private static DecimalFormat df = new DecimalFormat("#.##");
int i, p, f, x;
int pow(int n)
{
x=n;
p=1;
for(i=0; i<x ; i++)
{
p=p*x;
}
return p;
}
int fact(int n)
{
f=1;
x=n;
for(i=1; i<=x; i++)
{
f=f*i;
}
return f;
}
public static void main(String args[])throws IOException
{
int i, po, fa, no;
double s=0.0;
SeriesPowFact ob=new SeriesPowFact();
InputStreamReader input=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(input);
//BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter a number :");
no=Integer.parseInt(br.readLine());
for(i=1;i<=no;i++)
{
po=ob.pow(i);
fa=ob.fact(i);
s=s + (double)fa/po;
}
System.out.println("Series="+s);
DecimalFormat df = new DecimalFormat("#.###");
String formatted = df.format(s);
System.out.println(formatted); //prints 2.46
}
}
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