how to reuse previous variable value after closing program

Question

public class UseVariableValueAgain{

    public static void main(String args[]){
        int x=6;

        int y=7;
        int LastValue=0;// for first time
        LastValue=x+y+LastValue;

        System.out.println("result"+LastValue);
        Scanner scan = new Scanner(System.in);

        int x1=scan.nextInt();
        int y1=scan.nextInt();
        int LastValue1=0;
        LastValue1=x1+y1+LastValue1;//for first time 

        System.out.println("REsult using Scanner="+LastValue1);


    }

}
Ressult=13
5
6
Result using Scanner=11

when i execute this program i got 13 output by default and by using scanner i enter 5,6 and output is 11 , Now I want to use (13,11)values for next time when i re-execute the program. but it give same result

You'll need to store the value somewhere then; like a file or a database. — Elliott Frisch
– Elliott Frisch, Commented Mar 24, 2016 at 16:51
you'll need some persistence storage to store previous values — Ramanlfc
– Ramanlfc, Commented Mar 24, 2016 at 16:53
Possible duplicate of How to create a file and write to a file in Java? — fabian
– fabian, Commented Mar 24, 2016 at 16:55

Bajal · Accepted Answer · 2016-03-24 17:00:32Z

1

Your options in order of easiness:

1) Next time when you invoke the program, pass the values at the command line. java UseVariableValueAgain 13 11. You will have access to these values via args[] array now. Keep in mind you will have to parse this to integer as args is a String array.

2) Write these values to a file. (eg using BufferedWriter) and read it in the program using Scanner or BufferedReader;

3) Write the value to a database table. Read the values from the table in your program.

In all these options, you will have to check if this is a re-run by employing appropriate if-else conditions to check if the value needs to be read from user input or if it needs to be determined. If you are learning Java, I recommend trying all three options in that sequence.

answered Mar 24, 2016 at 17:00

Bajal

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Yashasvi Raj Pant · Accepted Answer · 2016-03-24 17:01:54Z

0

You need to write the previous value in a persistent storage(like file).

answered Mar 24, 2016 at 17:01

Yashasvi Raj Pant

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