10.1. Actual Parameter Vs Formal Parameter

Formal parameters are the parameters as they are known in the function/method definition.

Actual parameters are also known as arguments and are passed by the caller on method invocation (calling the method).

Let's write a class ActualAndFormalParameters to identify the actual and formal paramrters in method declaration and method call.

			package javatutorial;

			/**
			 * Example class to identify the actual and formal parameters in Java
			 * 
			 * @author f5java.com
			 */
			public class ActualAndFormalParameters {

				/**
				 * Display the info name, course and grade
				 */
				public void displayMethod (String name, String course, String grade){
					// A. Formal parameters are those defined in method declaration
					
					// Following are the formal parameters of this method
					// 1. formal parameter is name and type is String
					// 2. formal parameter is course and type is String
					// 3. formal parameter is grade and type is String
					
					System.out.println("Name : " + name); // Print details
					System.out.println("Course : " + course);
					System.out.println("Grade : " + grade);
				}
				
				
				public static void main(String[] args) {
					// local variables
					String studentName = "John";
					String studentcourse = "Java Programming Course";
					String studentGrade = "A";
					
					// Instantiate
					ActualAndFormalParameters parameters = new ActualAndFormalParameters();
					
					// B. Actual parameters are the parameters in the method call
					
					// Following are the actual parameters in the method call
					// 1. actual parameter: studentName
					// 2. actual parameter: studentCourse
					// 3. actual parameter: studentGrade
					
					parameters.displayMethod(studentName, studentcourse, studentGrade); // Method call
					
				}
			}