How does (i)+ (++i) {for i=1} becomes 4 and not 3?

Asked Jun 23 '21 at 21:03

Active Jun 23 '21 at 21:08

Viewed 86 times

how does my output come to be as 4 and not 3 in:

int i=1;
int k;

k=i + ++i;
cout<<k<<endl;

So, according to me what happens here is that the first i must be 1 and the (++i) must be 2. So, when they both are added the value of k must be 3 right? Ofcourse I'm missing something. But what?

asked Jun 23 '21 at 21:03

How

Where's the `for` loop? – Thomas Matthews Jun 23 '21 at 21:04
1

Search StackOverflow for "sequence points". – Thomas Matthews Jun 23 '21 at 21:04
1

You don't know if it will be as if `++i; k = i + i;` or `k = i; ++i; k += i;`. – Eljay Jun 23 '21 at 21:06
Please help me find a proper duplicate (C++, the currently linked one is C) – Ben Voigt Jun 23 '21 at 21:06
Today must be Increment Operator Day on Stackoverflow. This is like the third substantively identical question that got dupe-hammered. – Sam Varshavchik Jun 23 '21 at 21:07
@TedLyngmo: That's a slightly different case, here the object is only modified once, but there is a read unordered with respect to the modification. – Ben Voigt Jun 23 '21 at 21:10
@BenVoigt Agree - I removed the comment. – Ted Lyngmo Jun 23 '21 at 21:11
[The compiler output](https://godbolt.org/z/KKsn3E8EM) with enough warnings turned on may be helpful – Ted Lyngmo Jun 23 '21 at 21:12

How does (i)+ (++i) {for i=1} becomes 4 and not 3?

0 Answers0