function in java | types example
here's an explanation of functions in Java programming along with examples and short definitions:
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What is a Function in Java?
A function, also known as a method in Java, is a block of reusable code that performs a specific task. Functions promote code modularity, reusability, and maintainability. They help in breaking down complex programs into smaller, manageable units.
Structure of a Function
A function in Java consists of two main parts:
Function Declaration: This informs the compiler about the function's existence, including its name, return type, access modifier, and parameter list (if any). The syntax for a function declaration is:
Java
accessModifier returnType functionName(parameterList) {
// Function body
}
For example, the function declaration public int add(int a, int b); declares a function named add with public access modifier, an integer return type, two integer parameters, a and b, and an empty function body.
Function Definition: This provides the actual code that the function executes when it's called. The syntax for a function definition is:
Java
accessModifier returnType functionName(parameterList) {
// Function body
}
For example, the function definition public int add(int a, int b) { int sum = a + b; return sum; } defines the function add to calculate the sum of two integer values and return the result.
Types of Functions in Java
User-Defined Functions: These are functions created by the programmer to address specific needs within the program.
Library Functions: These are predefined functions provided by the Java standard library and offer a wide range of functionalities.
Example of a User-Defined Function:
Java
public class Adder {
public static int add(int a, int b) {
int sum = a + b;
return sum;
}
public static void main(String[] args) {
int num1 = 10;
int num2 = 20;
int result = add(num1, num2);
System.out.println("The sum of " + num1 + " and " + num2 + " is " + result);
}
}
This program defines a user-defined function add in the Adder class that takes two integer inputs and returns their sum. The main function calls the add function to calculate the sum of two numbers and prints the result.
Example of a Library Function:
Java
public class HelloPrinter {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
This program uses the standard library function System.out.println to print the message "Hello, World!" to the console.
Short Definitions:
Function Name: The identifier that uniquely identifies the function.
Return Type: The data type of the value returned by the function (void indicates no return value).
Access Modifier: Specifies who can access the function (public, private, protected).
Parameters: Optional input values passed to the function.
Function Body: The code that is executed when the function is called.
KeyWords:
java methods,function in java,
functional interface in java 8,
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