first loop, num = 3 sum = sum + num // sum becomes 3 sum++ // sum becomes 4 second loop, num = 2 sum = sum + num // sum becomes 6 sum++ // sum becomes 7

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After I have added 'sum++' to the code, the output has changed from 5 to 7, I wonder why?

'Keyboard.readInput()' is to read user input. In this case, the input are 3, 2, and -1 to stop the loop.

'Keyboard.readInput()' is to read user input. In this case, the input are 3, 2, and -1 to stop the loop.

C#

public class MyProgram { public void start() { int sum = 0; System.out.println("Enter number: "); int num = Integer.parseInt(Keyboard.readInput()); while (num >= 0) { sum = sum + num; System.out.print("Enter number: "); num = Integer.parseInt(Keyboard.readInput()); sum++; } System.out.println("Sum: " + sum); } }

To understand, just cycle the while loop, and you will see that:

first loop, num = 3 sum = sum + num // sum becomes 3 sum++ // sum becomes 4 second loop, num = 2 sum = sum + num // sum becomes 6 sum++ // sum becomes 7

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Comments

_Asif_
10-Jul-14 2:43am

+5 :)

Peter Leow
10-Jul-14 5:24am

Thank you, Asif.

there is nothing to wonder, Only you need to know what is increment operator and what it does.

read few article/tutorials about this operator and try to learn

Assignment, Arithmetic, and Unary Operators[^]

Java increment & decrement operator[^]

read few article/tutorials about this operator and try to learn

Assignment, Arithmetic, and Unary Operators[^]

Java increment & decrement operator[^]

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