Can anyone explain it to me that why we are getting 18 instead of 17

Question

https://code.sololearn.com/c3huj9apOlb5/?ref=app

Answer 1

Same problem answered in this thread.
https://www.sololearn.com/Discuss/2662995/?ref=app

Answer 2

The warning pretty much clearly informs you that there is a sequence point issue. You are trying to modify a variable more than once in a single expression and this behaviour is not so well defined in the C or C++ language. The output may differ for different compilers.

Answer 3

[Explanation for the Aman Sharma's code after line 6 ]

The following is my what I think:

1) We can get the hint from the definition of prefix increment("The prefix increment returns the value of a variable after it has been incremented.") that is first pre-increment both the variable a and then return the value of it.
like so,
i = 2
In our case, a = ++i + ++i;
Initial Value = 2
First Prefix = 3
Second Prefix = 4
Final Equation a = 4 + 4 = 8
So, it's 18.

2) Another reason maybe because of where and how C/C++ compiler stores variable during the execution.

(I play a bit with the code and got this amazing result, I am learning as well so I am confused too)

https://code.sololearn.com/czGw8Vrb3Sxd/?ref=app

Answer 4

Aman Sharma
The reason why it outputs 18 is not because of the incremention But because you did not print a new line. The first prints 1 and the second prints 8. And because it does no have new line, it will output 18. When kt should have been 1 and 8.

The output should have look like this:
1
8

The first one is because you used suffix incremention.
i++ + i++
Use the variable( 0 ) + Then used again th inremented variable ( 1 )
0 + 1 == 1
But in the next lines of the program, the value of i will become 2 becausw we have 2 incrementions. The second one is said by RKK and the thread I shared.

https://code.sololearn.com/cc9rT05E4551/?ref=app

Answer 5

[Explanation for the Aman Sharma's code after line 6 ]

MEMORY
i [ 2 ]

a = ++i + ++i;
We know the associativity of prefix operation is from Right to Left( R ---> L).

So ++i(the right one) gets executed first which will make the initial value of i from 2 to 3 and we have

MEMORY
i [ 3 ]

Again, ++i(the left one) gets executed which will make the value of i in memory incremented(from 3 to 4) and then update, we have

MEMORY
i [ 4 ]

So the most updated value of i in the memory is 4 so we can relate from the definition of prefix-increment( "The prefix increment returns the value of a variable after it has been incremented.") that the updated incremented value be returned that is
i = 4

So our equation becomes
a = 4 + 4 = 8
which is 8.

(correct me if I am wrong here)

Answer 6

《 Nicko12 》 No bro I am not talking about that
I am asking why the output Is 18 instead of 17.

Answer 7

Aman Sharma kindly read my answer and the first thread shared by 《 Nicko12 》 because there is no definite answer to this.

Answer 8

Aman Sharma which part?
You need to dry run yourself too.
Try to execute yourself with the help of copy and pencil, you'll understand well.

Answer 9

Woh

Answer 10

RKK I didn't get the last part.