For loop and while loop.

Question

1)
#include <iostream>
using namespace std;

int main() {
int x;
while (x++<10) {
x+=2;
}
cout<<x;
return 0;
}
Output:13

2)
#include <iostream>
using namespace std;

int main() {
int i;
for(i=0;i<=6;i++);
i+=5;
cout<<i;
return 0;
}
Output: 12

Can anyone please explain how is the output 13 and 12?

Answer 1

May I know, how much you understood till now? Where is the difficulty in code?

edit:

int main() {

int x;
while (x++<10) { //initially x=0; 0<10 is true, next post increment x++ cause x=1
x+=2; //x = 1+2=3 now after 1st iteartion

/*
in 2nd iteration 3<10 is true, next post increment x++ cause x=4
x+=2; x = 4+2=6 now after 2nd iteartion

in 3rd, 6<10 is true, next post increment x++ cause x=7
x+=2; x = 7+2=9 now

Next, 9<10 is true, next post increment x++ cause x=10
x+=2; x = 10+2=12 now
Next iteration 12<10 is false, loop stops here but x++ cause its value to be x=x+1=12+1=13. */
}
//so at end x=13 after the loop, its printed
cout<<x;
return 0;
}

Answer 2

Jayakrishna🇮🇳 thank you so much!🙌 just my silly mistake between x++ and ++x got me confused.
Thank you for clearing the doubt.💯

Answer 3

So you know how 2nd code works by for loop? Are you aware of semicolon after for loop, what is cause? If yes, then fine.. 👍👍

You're welcome..Neha Gawali