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Adding

Java Syntax, Level 4, Lesson 16

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I can't find the error.

Use the keyboard to enter numbers.
If the user enters -1, display the sum of all entered numbers and end the program.
-1 should be included in the sum.

Hint: one of the solutions to this problem uses the following construct:

while (true) {
    int number = read the number;
    if (check whether the number is -1)
        break;
}

Requirements:

The program should read the numbers from the keyboard.
If the user enters -1, the program should display the sum of all entered numbers and then end.
The program must calculate and display the sum of the entered numbers.
The program must use a for loop or a while loop.

package com.codegym.task.task04.task0442; /* Adding */ import java.io.*; public class Solution { public static void main(String[] args) throws Exception { //write your code here BufferedReader read = new BufferedReader(new InputStreamReader(System.in)); int sum = 0; while (true) { int num = Integer.parseInt(read.readLine()); if (num == -1) break; } if (num >= -1) sum += num; System.out.println(sum); } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

21 February 2021, 15:52

Line by line, this is what your code does: 14: reader from the cmd line is created 18: an int variable "sum" is created and set to 0 20: A while loop is declared that runs infinitely 21: a value is read from the command line and converted to an int, which is saved as "num" 25-26: checks if num is equal to -1 if true then the infinite while loop will be broken 28: if the above condition is false then the loop repeats 29-30: Checks if num equals -1, if so then it adds it to the sum 31: outputs sum So, there is one major problem that is preventing you from passing and some additional steps that can be improved with the above sequence: Main problem: - num is never added to sum, except for line 30 when num equals -1. This means that when line 31 is reached it will ALWAYS output -1 Additional: - line 29: the loop will never break unless -1 is entered. This means that this line will always be true when it is reached, otherwise the code would never exit the while loop. - Also you don't even need lines 29-30. The code should just add everything that is entered to sum.

hidden #10690840

Level 13

21 February 2021, 12:48

You need an addition condition to add to the loop. At the moment, the program sees this: When "num" is -1 we end the loop. And you should have this: When "num" is -1 we end the loop. If it isn't, add "num" to the "sum" result. Repeat it.

Sinisa

Level 11 , Banja Luka, Bosnia and Herzegovina

20 February 2021, 17:17

You don't need second condition: if (num>=-1). If sum+=num is out of loop, then it will not sum the entered numbers. However this task is not set clearly, if the user don't enter -1, the program will never exit the loop.

Nouser

Level 36 , Germany

20 February 2021, 17:12

lines 29, 30 should be inside the while loop and you should take care of negative numbers being added to the sum, too.