Final

Whenever we add ‘final’ in front of a variable, it means we can’t change the variable under any circumstances. In this example we use an int variable number, but we write it as NUMBER so we know it’s a constant.

// jamesprogram.java
class jamesprogram {

	public static void main (String[] args){
		
		cat catObject = new cat(10);
		
		for (int i=0;i<5;i++){
			catObject.add();
			System.out.printf("%s", catObject);
		}
		
	}
}
//cat.java
public class cat {
	
	private int sum;
	
	// declare final variable
	// as soon as we assign something to NUMBER
	// (initialize it) it cannot be changed, EVER
	// after that point
	private final int NUMBER; // Contants are in caps
	
	public cat(int x){
		NUMBER=x;
	}
	
	public void add(){
		sum+=NUMBER;
	}
	
	public String toString(){
		return String.format("sum = %d\n", sum);
	}
	
}

Outputs:

sum = 10
sum = 20
sum = 30
sum = 40
sum = 50

Leave a Reply