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Saravanan.G
• A function is a set of statements performing a task. In java
function is called as method.
[<access_specifier>] [<modifier>] <return_type> <function_name>([<parameter_list>])
{
Statement1;
Statement2;
.
.
Statementn;
}
Where,
<access_specifier> --- is either public, private, protected or default.
<modifier> --- is a keyword which modifies the function. It can be static, volatile, synchronized
etc.
<return_type> --- data type of the variable which is returned from the function
<function_name> --- name of the function
<parameter_list> --- list of data type and variable pair separated by a comma.
•
•
•
•
Function which does not accept and does not return
Function which accepts but does not return
Function which accepts and returns
Function which does not accept but returns
public void add()
{
BufferedReader br = new BufferedReader(new
InputStreamReader(System.in));
System.out.println(“Enter first number”);
int a = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int b = Integer.parseInt(br.readLine());
int sum = a + b;
System.out.println(“The sum of “ + a + “ and “ + b +
“ is : “ + sum);
}
public static void main(String[] args)
{
//Create an object of the class
Calculator calc = new Calculator();
//Call the add function
calc.add();
}
import java.io.*;
public class Calculator
{
public void add() throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int a = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int b = Integer.parseInt(br.readLine());
int sum = a + b;
System.out.println(“The sum of “ + a + “ and “ + b + “ is : “ + sum);
}
public static void main(String[] args) throws IOException
{
Calculator calc = new Calculator();
//Call the add function
calc.add();
}
}
• WAP to simulate a simple calculator using functions(1st type)
• Let the name of the functions be
•
•
•
•
•
findSum()
findDifference()
findProduct()
findQuotient()
findRemainder()
public void add(int a, int b)
{
int sum = a + b;
System.out.println(“The sum of “ + a + “ and “ +
b + “ is : “ + sum);
}
public static void main(String[] args)
{
//Create an object of the class
Calculator calc = new Calculator();
//Call the add function
calc.add(10, 20);
}
public class Calculator
{
public void add(int a, int b)
{
int sum = a + b;
System.out.println(“The sum of “ + a + “ and ” + b +
“ is : ” + sum);
}
public static void main(String[] args)
{
Calculator calc = new Calculator();
//Call the add function
calc.add(10, 40);
}
}
import java.io.*;
public class Calculator
{
public void add(int a, int b)
{
int sum = a + b;
System.out.println(“The sum of “ + a + “ and “ + b + “ is : “ + sum);
}
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int x = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int y = Integer.parseInt(br.readLine());
Calculator calc = new Calculator();
//Call the add function
calc.add(x, y);
}
}
import java.io.*;
public class Calculator
{
public void add(int a, int b)
{
int sum = a + b;
System.out.println(“The sum of “ + a + “ and “ + b + “ is : “ + sum);
}
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int x = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int y = Integer.parseInt(br.readLine());
Calculator calc = new Calculator();
//Call the add function
calc.add( x + y , x - y );
}
}
• WAP to simulate a simple calculator using functions(2nd type)
• Let the name of the functions be
•
•
•
•
•
findSum()
findDifference()
findProduct()
findQuotient()
findRemainder()
public int add(int a, int b)
{
int sum = a + b;
//Return the variable sum
return sum;
}
public int add(int a, int b)
{
//Return an expression
return a + b;
}
public class Calculator
{
public int add(int a, int b)
{
int sum = a + b;
return sum;
}
public static void main(String[] args)
{
Calculator calc = new Calculator();
//Call the add function and store the returned value
int result = calc.add(10, 40);
System.out.println(“The sum is “ + result);
}
}
import java.io.*;
public class Calculator
{
public int add(int a, int b)
{
int sum = a + b;
return sum;
}
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int x = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int y = Integer.parseInt(br.readLine());
Calculator calc = new Calculator();
//Call the add function
int result = calc.add(x, y);
System.out.println(“The sum of ” + x + “ and ” + y + “ is : ” + result);
}
}
import java.io.*;
public class Calculator
{
public int add(int a, int b)
{
int sum = a + b;
return sum;
}
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int x = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int y = Integer.parseInt(br.readLine());
Calculator calc = new Calculator();
//Call the add function
int result = calc.add(x
+ y, x - y);
System.out.println(“The sum of “ + x + “ and “ + y + “ is : “ + result);
}
}
import java.io.*;
public class Calculator
{
public double add(double a, double b)
{
double sum = a + b;
return sum;
}
public static void main(String[] args) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
double x = Double.parseDouble(br.readLine());
System.out.println(“Enter second number”);
double y = Double.parseDouble(br.readLine());
Calculator calc = new Calculator();
//Call the add function
double result = calc.add(x, y);
System.out.println(“The sum of “ + x + “ and “ + y + “ is : “ + result);
}
}
• WAP to simulate a simple calculator using functions(3rd type)
• Let the name of the functions be
•
•
•
•
•
findSum()
findDifference()
findProduct()
findQuotient()
findRemainder()
public int add() throws IOException
{
System.out.println(“Enter first number”);
int a = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int b = Integer.parseInt(br.readLine());
int sum = a + b;
//Return the variable sum
return sum;
}
import java.io.*;
public class Calculator
{
public int add() throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
int a = Integer.parseInt(br.readLine());
System.out.println(“Enter second number”);
int a = Integer.parseInt(br.readLine());
int sum = a + b;
//Return the variable sum
return sum;
}
public static void main(String[] args) throws IOException
{
Calculator calc = new Calculator();
//Call the add function
int result = calc.add();
System.out.println(“The sum of is : “ + result);
}
}
import java.io.*;
public class Calculator
{
public double add() throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Enter first number”);
double a = Double.parseDouble(br.readLine());
System.out.println(“Enter second number”);
double b = Double.parseDouble(br.readLine());
double sum = a + b;
//Return the variable sum
return sum;
}
public static void main(String[] args) throws IOException
{
Calculator calc = new Calculator();
//Call the add function
double result = calc.add();
System.out.println(“The sum of is : “ + result);
}
}
• Two functions are said to be overloaded functions if the
function names are same and parameter list is unique that is
• The number of parameters in two functions must be different.
• But if the number of parameters are same, then the data types of
corresponding parameters in two functions must be different.
• A constructor is like a function having same name as class name and
does not have a return type
• A constructor is always called during instantiation
• There are two types of constructors
• Non-parameterized constructor – Constructor which does not have any
parameters
• Parameterized Constructor – Constructor which has a list of parameter
• Default Constructor: Whenever the programmer does not define a
constructor explicitly a default constructor is provided by the
compiler
• Are also called as class
variables
• There is only one copy of a
static variable available for
the entire class
• Example:
• static int numOfStudents;
• Static variables can be
accessed directly using class
name. No need of creating
an object.
• Example: Math.PI
• Are also called as instance
variables
• There is one copy of nonstatic variable in every
instance of that class
• Example:
• String name
• Non-static variables can be
accessed only by an object
• Example:
Student obj = new Student();
obj.name = “comp”;
• Static functions can directly be
called using the class name,
without creating an object.
• Example:
double Math.pow(int, int)
• A function can be made as a
static function by using a static
modifier in the function
prototype
static void main()
{
}
• Non-static functions should
be called only using objects.
• Example:
char charAt(int)
String toUpperCase()
• A member function is by
default a non-static function
void add()
{
}