Java 2 lines terminal input

Question

For a school assignment I have to make a program that reads two numbers from the terminal and then processes those numbers. The program has to automatically process those two values once they have been entered. The code I have so far is down below, but you have to press Enter before the program multiplies the numbers, the user shouldn't have to press enter three times, but only two times.

public static void man(String[] args) throws NumberFormatException, IOException{ BufferedReader reader = new BufferedReader( new InputStreamReader(System.in)); int count = 0; int width = 0; int height= 0; String number; while( (number = reader.readLine())!=null && count < 2 ) { while( count < 2 ){ if( count == 0) { width = Integer.parseInt( number); count++; break; } else if (count == 1) { height = Integer.parseInt( number); count++; break; } } } System.out.println( width * height ); }

This is how the user has to use the program at the moment

Enter number 1 and press enter
Enter number 2 and press enter
Enter nothing and press enter
The program prints the multiplied numbers

But this is how the user should use the program at the moment:

Enter number 1 and press enter
Enter number 2 and press enter
The program prints the multiplied numbers

Of course my program has to do something different for the assignment but I have changed it a little bit to make it easier to explain here.

Thank you for you help in advance!

Your main method has the name man. Correct it please.

Christian Tapia
– Christian Tapia

2013-10-28 18:58:28 +00:00
Commented Oct 28, 2013 at 18:58 — Christian Tapia
– Christian Tapia, Commented Oct 28, 2013 at 18:58

arcy · Accepted Answer · 2013-10-28 19:12:29Z

Since you're doing a school assignment, I'll make another suggestion: eliminate the confusing assignment-within-a-condition. I know you've seen this somewhere, and will continue to see it in a lot of places, and will even run into people who advocate it passionately, but I think it tends to confuse things. How about:

for (int i=0; i<2; i++) { String number = reader.readLine(); if (i == 0) { height = Integer.parseInt(number); } else { width = Integer.parseInt(number); } }

Christian Tapia · Accepted Answer · 2013-10-28 19:01:41Z

Try this modifications:

public static void main(String[] args) throws NumberFormatException, IOException { BufferedReader reader = new BufferedReader(new InputStreamReader( System.in)); int count = 0; int width = 0; int height = 0; String number; while (count < 2) { // Just 2 inputs number = reader.readLine(); if (count == 0) { width = Integer.parseInt(number); count++; } else if (count == 1) { height = Integer.parseInt(number); count++; } else // If count >= 2, exits while loop break; } System.out.println(width * height); }

Your method is much easier to understand, so I'm going to use your method but Aaron's method also worked. Thank you for your very fast answer!

Aaron · Accepted Answer · 2013-10-28 18:58:58Z

0

Do that count < 2 check before the readLine(), otherwise it will try to read a number before it checks the count.

I.e those checks are evaluated left to right

answered Oct 28, 2013 at 18:58

Aaron

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1 Comment

user2929285 Over a year ago

Thank you! This worked very well, but Christian´s method is easier to understand so I´m going use that one. Thank you very much for your fast answer!

vj5 · Accepted Answer · 2013-10-28 19:06:25Z

use java.util.Scanner class for user input

Scanner scanner = new Scanner(System.in); int width = scanner.nextInt(); int height = scanner.nextInt(); scanner.close(); System.out.println( width * height );

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