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public class Main {

public static void main(String[] args) {
    
    int i=1,sum=0;
    
    while(i<=6) {
        sum+=i++; 
    }
    System.out.println(sum);

}

}

this is java eclipse code, and it prints 21 normally But i don't understand that "sum += i++; " code. I understood the meaning of that code as, 1+1 2+1 3+1 4+1 5+1 6+1 -> 2+3+4+5+6 -> 20. How is that code calculated in a while loop? And why not ++i?

Seung-nam
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    You need to read up about the pre and post increment operators. – cup Jul 28 '22 at 17:08
  • Currently the calculation is basically `1 + 2 + 3 + 4 + 5 + 6`. *"And why not ++i?"* - When you change it to that, what happens to the result? – David Jul 28 '22 at 17:08
  • Right. The value of `i++` in an expression is the value of `i`. As a side effect, it also bumps the value stored in `i`, but the bumped value isn't part of the expression. The value of `++i` in an expression is `i+1`. – Tim Roberts Jul 28 '22 at 17:14

1 Answers1

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the answer is 21 because we add each iteration of the loop in the sum. so at each verification if a number is less than or equal to <=6 we add each in the variable sum. so the increment is after verification and not make the post incrementention. #JAVA

Alain Kazadi
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