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POJava clarification on += assignment operator
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  1. POJava clarification on += assignment operator
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    copied!<p>I'm a bit confused about how += assignment operator works. I know that x += 1 is x = x+1. However, in this code there is a string variable called 'String output' and initialized with an empty string. My confusion is that that there are 5 different outputs for the variable 'output' but I don't see where it's being stored. Help clarify my misunderstanding. I can't seem to figure it out.</p> <pre><code>import java.util.Scanner; public class SubtractionQuiz { public static void main(String[] args) { final int NUMBER_OF_QUESTIONS = 5; //number of questions int correctCount = 0; // Count the number of correct answer int count = 0; // Count the number of questions long startTime = System.currentTimeMillis(); String output = " "; // Output string is initially empty Scanner input = new Scanner(System.in); while (count &lt; NUMBER_OF_QUESTIONS) { // 1. Generate two random single-digit integers int number1 = (int)(Math.random() * 10); int number2 = (int)(Math.random() * 10); // 2. if number1 &lt; number2, swap number1 with number2 if (number1 &lt; number2) { int temp = number1; number1 = number2; number2 = temp; } // 3. Prompt the student to answer "What is number1 - number2?" System.out.print( "What is " + number1 + " - " + number2 + "? "); int answer = input.nextInt(); // 4. Grade the answer and display the result if (number1 - number2 == answer) { System.out.println("You are correct!"); correctCount++; // Increase the correct answer count } else System.out.println("Your answer is wrong.\n" + number1 + " - " + number2 + " should be " + (number1 - number2)); // Increase the question count count++; output += "\n" + number1 + "-" + number2 + "=" + answer + ((number1 - number2 == answer) ? " correct" : " wrong"); } long endTime = System.currentTimeMillis(); long testTime = endTime = startTime; System.out.println("Correct count is " + correctCount + "\nTest time is " + testTime / 1000 + " seconds\n" + output); } } </code></pre>
 

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