The problem is to write a program in 'C' to find the greatest of 2 given
numbers... Easy? huh
here's the catch
do not use 'if' or any conditional statements
if u want it to be a little more tougher you can use the if but this time
no relational operators or any of the predefined functions....
Can someone please help me solve the problem....
Nov 14 '05
89  3475 
"infobahn" <in******@btint ernet.com> wrote in message
news:41******** *******@btinter net.com... If an electronic engineer can't get it with all those hints,
there's something wrong with the awards process.
You gave away more than I would have! :-)
The only additional clue I was going to add was
the word "array".
-Mike
Easy - use inline assembly.
Or subtract one from the other and the test the sign bit.
"purifier" <cn******@gmail .com> wrote in message
news:19******** *************** *******@localho st.talkaboutpro gramming.com... The problem is to write a program in 'C' to find the greatest of 2 given
numbers... Easy? huh
here's the catch
do not use 'if' or any conditional statements
if u want it to be a little more tougher you can use the if but this time
no relational operators or any of the predefined functions....
Can someone please help me solve the problem....
People always like to think that the help they're giving is of commercial
value. If they think otherwise, they'll jump on the 'homework' bandwagon.
Happens every time.
"purifier" <cn******@gmail .com> wrote in message
news:8a******** *************** *******@localho st.talkaboutpro gramming.com... It's a real sad thing to know, Sir... I didn't expect that my post would
make you think that it was my homework... I'm an Electronics Engineer, but
i'm interested a lot in programming... One of my friends asked me this
question in a mail. I just pasted that mail here... For your information i
even said "Can you please help me solve the problem" Why would I say huh
and all kinds of stuff and then ask people to solve the problem? I could
have directly given the problem...
Anyway, Sorry if i mislead you guys... Thank you for the replies.. Atleast
if possible, please give me some ideas...
Thank You
purifier wrote: The problem is to write a program in 'C' to find the greatest of 2 given
numbers... Easy? huh
here's the catch
do not use 'if' or any conditional statements
if u want it to be a little more tougher you can use the if but this time
no relational operators or any of the predefined functions....
Can someone please help me solve the problem....
max(a,b) = (abs(a-b)+a+b)>>1;
this hint has of course some obvious limitations :)
przemek drochomirecki
Hi~ all
i think that this is the problem about getting sign bit of numbers...
this is very easy... see follow code lines...
you can simplfy multiple lines to a line...
int main(int argc, char *argv[])
{
int a = 2.0;
int b = -23.1;
int lagestNumber = 0;
int signBitCount = (sizeof(int) * 8) - 1;
int signBitMask = 0x1 << signBitCount;
int a_minus_b = a - b;
int b_minus_a = b - a;
int signBitA = 0;
int signBitB = 0;
signBitA = ((unsigned)a_mi nus_b & signBitMask) >> signBitCount;
signBitB = ((unsigned)b_mi nus_a & signBitMask) >> signBitCount;
x = (signBitA ^ 0x1) * a + (signBitB ^ 0x1) * b;
printf("lagestN umber = %d\n", lagestNumber);
return 0;
}
"purifier" <cn******@gmail .com> wrote in message
news:19******** *************** *******@localho st.talkaboutpro gramming.com... The problem is to write a program in 'C' to find the greatest of 2 given
numbers... Easy? huh
here's the catch
do not use 'if' or any conditional statements
if u want it to be a little more tougher you can use the if but this time
no relational operators or any of the predefined functions....
Can someone please help me solve the problem....
Nick Austin wrote: On 16 Jan 2005 16:01:42 -0800, "Peter Nilsson" <ai***@acay.com .au>
wrote:
[...]The following uses strtol() to convert arguments on the command
line, and printf() to output the maximum. Otherwise, it doesn't
use any conditional, logical, equality or relational operators,
nor does it use any selection or iteration statements.
[...]typedef unsigned long q1;
q1 q2(q1 q3,q1 q4,q1 q5,q1 >q6)
{
return(q5-q6)*(((((q3-q4)&(q4-q3)
)+2)/(((q3-q4)&(q4-q3))+1))-1)+q6;}
I don't think that's portable, namely the use of the bitwise
operator:
( q3 - q4 ) & ( q4 - q3 )
It seems to me that it assumes twos compliment and could give the
wrong answer on other architectures.
"Two's complement" applies to _signed_ integers. The quoted expression
operates on unsigned integers, for which there is only one choice
of representation, namely, pure binary, and for which the behaviour on
overflow is well defined.
--
Peter
Bonj wrote:
People always like to think that the help they're giving is of
commercial value. If they think otherwise, they'll jump on the
'homework' bandwagon. Happens every time.
Please don't toppost. As you can see, doing so has lost all
context here. As a matter of fact the 'homework' rejection is
designed to avoid creating a class of useless programmers who have
never learned to do anything themselves. Those that make efforts
but run into difficulties, and demonstrate it by posting their
work, usually get help.
--
"If you want to post a followup via groups.google.c om, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
À̱â¿î wrote:
Please don't top post in comp.lang.c. Hi~ all
i think that this is the problem about getting sign bit of numbers...
this is very easy... see follow code lines...
you can simplfy multiple lines to a line...
Missing inclusion of <stdio.h> or prototype for printf.
The behaviour of printf is therefore undefined.
int main(int argc, char *argv[])
{
int a = 2.0;
int b = -23.1;
This is not _wrong_ wrong, just wrong. ;)
int lagestNumber = 0;
int signBitCount = (sizeof(int) * 8) - 1;
A byte may have more than 8 bits. An int may have padding bits.
So, your shift count can be wrong in two ways.
int signBitMask = 0x1 << signBitCount;
Potential undefined behaviour. Even if the behaviour is defined for
some implementations , it may still be the wrong bit mask.
int a_minus_b = a - b;
int b_minus_a = b - a;
Potential overflow for arbitrary a and b.
int signBitA = 0;
int signBitB = 0;
signBitA = ((unsigned)a_mi nus_b & signBitMask) >> signBitCount;
signBitB = ((unsigned)b_mi nus_a & signBitMask) >> signBitCount;
An unsigned int need not use the corresponding int sign bit as a
value bit. So your cast may produce zero if a_minus_b is INT_MIN.
x = (signBitA ^ 0x1) * a + (signBitB ^ 0x1) * b;
printf("lagestN umber = %d\n", lagestNumber);
lagestNumber is 0 here.
return 0;
}
--
Peter
Nick Austin wrote: On 16 Jan 2005 16:01:42 -0800, "Peter Nilsson" <ai***@acay.com .au>
wrote:
[...]The following uses strtol() to convert arguments on the command
line, and printf() to output the maximum. Otherwise, it doesn't
use any conditional, logical, equality or relational operators,
nor does it use any selection or iteration statements.
[...]typedef unsigned long q1;
q1 q2(q1 q3,q1 q4,q1 q5,q1 >q6)
{
return(q5-q6)*(((((q3-q4)&(q4-q3)
)+2)/(((q3-q4)&(q4-q3))+1))-1)+q6;}
I don't think that's portable, namely the use of the bitwise
operator:
( q3 - q4 ) & ( q4 - q3 )
It seems to me that it assumes twos compliment and could give the
wrong answer on other architectures.
If unsigned integers looks like two's complement (signed) integers,
it's because two's complement integers look like unsigned integers. ;)
Unsigned types must use 'pure binary', and the behaviour on overflow
is well defined.
--
Peter
On Mon, 17 Jan 2005 08:02:08 +0000, Bonj wrote: Easy - use inline assembly.
The question was to write a program in C, and C has no inline assembly.
Or subtract one from the other and the test the sign bit.
Something along those lines may work although making it portable would be
a challenge.
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