Java Basic(48)-Final

public class tuna {

private int sum;

private final int NUMBER; → final 價值不能改變它

public tuna(int x){

NUMBER = x;

}

public void add(){

sum+=NUMBER; → sum 可以改變，因為它不是 final

}

public String toString(){

return String.format("sum = %d\n", sum);

}

}

class apples{

public static void main(String[] args){

tuna tunaObject = new tuna(10); →NUMBER的值是10

for(int i=0; i<5; i++){

tunaObject.add(); -->調用add方法()

System.out.printf("%s",tunaObject);

}

}

}

這是運行時的結果：

sum = 10

sum = 20

sum = 30

sum = 40

sum = 50