Why my program in not exiting out of while loop?

Question

Code:

int size=0;
Scanner in = new Scanner(System.in);     
System.out.println("Enter size of the Graph");
size = in.nextInt();
System.out.println(size);
for (int i = 1; i <= size; i++) {
    Scanner in2 =new Scanner(System.in);
    while(in2.hasNextInt()){
        int num = in2.nextInt();
        System.out.print("(" + i + "," + num + ")"+",");
        System.out.println();
    }
    System.out.println("out of the while loop");
}

Input & Output:

Enter size of the Graph
4
4
2 3 4
(1,2),
(1,3),
(1,4),
2 5 6
(1,2),
(1,5),
(1,6),

As you can see my program doesn't exists while loop. It still prints the value for i=1. What I am doing wrong?

Then you should enter EOF - or the program will constantly wait for the next feed. Are you using windows or linux? — amit
– amit, Commented Nov 15, 2012 at 6:05
Provide any character input. That will take you out of the loop. — Shashank Kadne
– Shashank Kadne, Commented Nov 15, 2012 at 6:06

amit · Accepted Answer · 2012-11-15 06:07:50Z

1

Your program is constantly waiting for a new feed, in order to terminate it - you should indicate the input was ended (or provide a non int input).

To indicate the feed ended - you should provide EOF - which is ctrl+D in linux and ctrl+Z in windows.

answered Nov 15, 2012 at 6:07

amit

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2 Comments

Shashank Kadne Over a year ago

Out of curiosity, how do I do it in eclipse console?

amit Over a year ago

Same way. feed the EOF to the CLI of the console.

Bhesh Gurung · Accepted Answer · 2012-11-15 06:14:23Z

1

int num = in2.nextInt();

try adding in2.nextLine(); after that.

Note:

You shouldn't be doing new Scanner(System.in); multiple times.

Scanner in2 = new Scanner(System.in); // this is useless just use in

edited Nov 15, 2012 at 6:14

answered Nov 15, 2012 at 6:06

Bhesh Gurung

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