Explain the output of this program.
#include<stdio.h>
main()
{
int i=2;
if(i+=2 && i==9)
printf("true %d ",i);
else
printf("false %d ",i);
}
Excepted output:
False 4
Actual output:
True 2
1 Like
I’m not so good in C/C++, probably something with operator priorities…
When I modified a code little bit
#include<stdio.h>
main()
{
int i=2;
if ( (i+=2) && (i==9) )
printf("true %d ",i);
else
printf("false %d ",i);
}
I’m getting false 4…
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if i take if statement as "if(i= i+2 && i==9)
then the output is coming as false 0
3 Likes
okay…now i am guessing something…
lets start…
first the compiler will take i+=2;
then i will be equal to 4…
then it will consider the bitwise AND operator “&&” with “9”…
ans bitwise AND operator of "4 AND 9 " is equal to 1…
thus if statement will work as it has if(1)…(1 in it)…
ans thus it will print true 2…
like it if you agree… -_- …
3 Likes
Okay i got it…
Since == has higher precedence,
–> i==9 wil return 0
–> Then comes && with precedence higher than +=, so 0 && 2 is 0
–> and at last i+=0 is i itself;
[[ So Output was True 2. ]]
3 Likes
@rishabprsd7
Thanks for explaining it.I was taking the expression separately. I was wrong there:)
Have been thinking for long,but then finally got that.Thank you!!
i know that… but my question is different
but i+=2 means same as i = i+2…
isn’t it…???
3 Likes
@rishabhprsd7
Why is the last step i+=0,instead it is i+=2?After the if statement,i will become 4.(i==9) just comparing,it won’t change i to 0.
read the previous step…
so 0 && 2 is 0
exactly bro,thts i want to know that ,if both are same ,then y the answer is different…
exp: i+=2 && i==9
According to operator precedence, == has highest precedence, So
Remains unoperated: (i+=2 &&), First opt. : i==9 which will return 0,
Now,
Exp becomes i+=2 && 0, As && has highest precedence,
Remains unoperated: (i+=), Second Opt, : 2 && 0 which will return 0 again,
Exp becomes i+=0, and now += has precedence, (only left operator in exp), So exp becomes i=i+0 and so i=i thus value of i is itself, i.e. 2.
Sorry for Bad English…!!
1 Like
welcome… 