Logical operators...

[shinelakshmanan]

main( )
{
int i= -3, j=2, k=0, m;
m=++i | | ++j && ++k;
printf("\n%d%d%d%d",i,j,k,m);
}

I am expecting the output of this code as

-2,2,1,1

but the compiler is giving
-2,2,0,1
can anyone tell me Y it is so?

[Banfa]

Why are you expecting -2,2,1,1 ?

Anyway

m=++i | | ++j && ++k;

is equivilent to

m=++i | | (++j && ++k);

it evaluates i++ this is -2, logically this is equivilent to true

true || anything = true

therefore it doesn't bother evaluating (++j && ++k) as it already has the result of the expression.

This is a feature that is unique (and very useful) to the logical operators but does mean that you have to be careful about putting expressions that actually do something into if statements etc.

[shinelakshmanan]

Why are you expecting -2,2,1,1 ?

Anyway

m=++i | | ++j && ++k;

is equivilent to

m=++i | | (++j && ++k);

it evaluates i++ this is -2, logically this is equivilent to true

true || anything = true

therefore it doesn't bother evaluating (++j && ++k) as it already has the result of the expression.

This is a feature that is unique (and very useful) to the logical operators but does mean that you have to be careful about putting expressions that actually do something into if statements etc.

cant we treat,

m=++i | | ++j && ++k as
m=(++i | | ++j) && ++ k
as post increment operators are having left to right associativity.....
its not clear to me if u clear me that I will be grateful.....

[shinelakshmanan]

I got the point,
as && operator is having higher priority then the || operator compiler will look for first occurence of && and combine the left and right operator in the parantheses,
thats why,
m=++i | | ++j && ++k
will be treated as
m=++i || (++j&& ++k) and not as
m=(++i || ++j) && ++k
Thanks a lot.....

[akshaycjoshi]

Hello friends
We all know that () has the highest priority.consider the expression--
int x=y=z=-1;
z= ++x || ++y && ++z;
In this by writing as z= (++x || ++y) && ++z;
there is no effect on x,y,z.
Why .According to prcedence relationship (++x || ++y ) should be calculated first ??