What is i++ and ++i operator, how do they work

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#include<bits/stdc++.h>
using namespace std;

int main()
{
int i = 5;

int ans = (i++) *(++i);

cout << ans << endl;

return 0;
}

This code gives output 35 and i am not able to understand what is happening there

What I have tried:

nothing i can try in this, i cant find the solution for this

Posted 10-Jul-18 18:59pm

Member 13906667

Updated 10-Jul-18 20:19pm

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Mehdi Gholam 11-Jul-18 1:44am

35 = 5 * 7, work it out.

Member 13906667 11-Jul-18 2:15am

how???

2 solutions

Solution 1

Basically, don't do that!
See here: Why does x = ++x + x++ give me the wrong answer?[^]

Posted 10-Jul-18 19:46pm

OriginalGriff

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Gerry Schmitz · Accepted Answer · 2018-07-10T20:19:00

Solution 2

Works out to:

int ans = i * ((i+1)+1);

The first "i" is 5; the "second reference" to "i" gets i++ and then ++i (7) before "*" is evaluated.

Order matters; otherwise you get 36.

Posted 10-Jul-18 20:19pm

Gerry Schmitz

Comments

Member 13906667 11-Jul-18 2:41am

what about (++i)*(i++)

[no name] 11-Jul-18 11:02am

What about it?

I said "order matters", and in that case the answer is 36.

(i++ is "last"; so its (6 * 6); with i ending up as 7 (again); but after "ans" is calculated.