Thread: Something strength !!!!!!!

Please look at following 'C' code :

main()
{
char c1;
int i1;
char c2;

printf("%u %u %u", &c1, &i1, &c2);
}


I got output of the above mentioned code is :

65497 65498 65501


Here the difference between first two numbers is 1 and it is ok as the size of char type is 1. But I want to know why the difference between 2nd and 3rd number is 3, while the size of int data type is only 2. So acording to me the output shoud be as follows:

65497 65498 65500

Can anybody please tell me why this happens ?

Thanking You,

16 bit compiler? DOS? Probably one or both.

>16 bit compiler? DOS? Probably one or both.

No.....I have ran this program fragment on 32-bit computer running on Windows'98.

>And it really doesn't matter where the compiler chooses to put >things into memory -- the compiler gets to put them anywhere it >feels like.

Do you mean that the efficiency factor particulary for memory allocation is completley depend on compiler.

Pl. look at following two code fragments: Suppose both are running on 16 bit computer and also compiled for 16 bit.

1.
main()
{
int i;
char c;

printf("%c %d",c,i);
}

2.
main()
{
char c;
int i;

printf("%c %d",c,i);
}

What I am thinking is first one will execute faster than second one. Faster by 1 instuction cycle. because according to me both are assiged at access boundary.

Now if allocation is depend completly on compiler then I think we don't have to look at this point..... is it ok ???

There is no point in optimizing most code. If you really need to, use the compiler flags which do so. Other than that, use a profiler on it to see where your bottlenecks are and rethink your algos. It's pointless to optimize "Hello World!".

Quzah.

Every cycle counts, if you loop 8,000,000,000 times at some point then it will make a minute difference if you have three or four extra cycles in each loop

I'm newer to c than I am to assembly but i dont think just because your programming higher level for faster processors that you can say there is no point optimizing code

Quzah's point is that you should first find out where and what to optimize before starting to throw in wild optimization guesses.

Kinasz, you are right.....but I was thinking in this way because I think it is required at core level. Suppose in future I will get some microcontroller based work or some embedded system based work which is of my interest (though I haven't any experience yet towards this side), then I think knowlege about this type of technics will be very helpfull