Positive random number

[deepak]

Hi,

Can someone give the standard function which can create positive
integer value in C?

Thanks,
Deepak

 

[Richard Heathfield]

deepak said:

Hi,

Can someone give the standard function which can create positive
integer value in C?

What does your textbook say about the generation of random numbers?

 

[santosh]

Hi,

Can someone give the standard function which can create positive
integer value in C?

Thanks,
Deepak

Look-up rand.

 

[divyank.rastogi]

Look-up rand.

You may want to man for rand series entirely; e.g. you may want to use
srand, and seed it with something like your system time to generate
random sequences, etc.

 

[Tor Rustad]

Hi,

Can someone give the standard function which can create positive
integer value in C?

There is no standard C function that creates numbers out of nothing.

If you are rather looking for a pseudo-random generator, see the C FAQ.

 

[CBFalconer]

There is no standard C function that creates numbers out of nothing.

However, the sequence "i = N;" is fairly safe, as long as N
represents a sequence of numeric digits (not including the '-'
sign) which represents a value <= INT_MAX. This even has the
elegant characteristic of allowing you to pick your own integer
value (within broad limits).

Another sophisticated sequence (which is not always possible) is:

if (i < 0) i = -i;

HTH

 

[Jack Klein]

Hi,

Can someone give the standard function which can create positive
integer value in C?

Other's have talked about "rand()", but I don't see anything in your
post that requires it. Here's a function guaranteed to meet the
requirement you asked for in the body of your message:

int create_positive_integer_value_in_C(void)
{
return 42;
}

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.learn.c-c++
http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

 

[Keith Thompson]

Other's have talked about "rand()", but I don't see anything in your
post that requires it.

[...]

The subject was "Positive random number". That information should
have been in the body of the original post.

 

[jaysome]

Other's have talked about "rand()", but I don't see anything in your
post that requires it. Here's a function guaranteed to meet the
requirement you asked for in the body of your message:

int create_positive_integer_value_in_C(void)
{
return 42;
}

Definitely *not* guaranteed.

In C99, section 5.2.4.1 Translation limits:

"The implementation shall be able to translate and execute at least
one program that contains at least one instance of every one of the
following limits:

....

31 significant initial characters in an external identifier..."

The identifier "create_positive_integer_value_in_C" is an external
identifier with 34 characters, and thus exceeds the minimum number of
characters *guaranteed* to be accepted by the standard. In C90, the
minimum was a paltry six characters.

Now, an identifier such as "create_positive_int_value_in_C" (30
characters) is acceptable in C99, but not necessarily in C90, though
arguably it is acceptable in most--if not all--C90 compilers in the
real world (for that matter, so is
"create_positive_integer_value_in_C" :^)

 

[santosh]

Definitely *not* guaranteed.

In C99, section 5.2.4.1 Translation limits:

"The implementation shall be able to translate and execute at least
one program that contains at least one instance of every one of the
following limits:

...

31 significant initial characters in an external identifier..."

The identifier "create_positive_integer_value_in_C" is an external
identifier with 34 characters, and thus exceeds the minimum number of
characters *guaranteed* to be accepted by the standard. In C90, the
minimum was a paltry six characters.

What part of "31 significant initial characters" did you not understand.
Jack's function name will only cause problems if he happened to have
defined another identifier with the same sequence of 31 initial
characters.

 

[Joachim Schmitz]

What part of "31 significant initial characters" did you not understand.
Jack's function name will only cause problems if he happened to have
defined another identifier with the same sequence of 31 initial
characters.

What part of "Definitely *not* guaranteed" didn't you understand? )

Bye, Jojo

 

[Johannes Bauer]

Other's have talked about "rand()", but I don't see anything in your
post that requires it.

[...]

The subject was "Positive random number". That information should
have been in the body of the original post.

http://xkcd.org/221/

)

Greetings,
Johannes

 

[pete]

On Tue, 18 Dec 2007 00:43:10 -0800 (PST), deepak
Can someone give the standard function which can create positive
integer value in C?
Other's have talked about "rand()",
but I don't see anything in your
post that requires it.

[...]

The subject was "Positive random number". That information should
have been in the body of the original post.

Th return value of rand isn't guaranteed to be positive.

 

[Richard Heathfield]

pete said:

On Tue, 18 Dec 2007 00:43:10 -0800 (PST), deepak
Can someone give the standard function which can create positive
integer value in C?
Other's have talked about "rand()",
but I don't see anything in your
post that requires it.
[...]

The subject was "Positive random number". That information should
have been in the body of the original post.

Th return value of rand isn't guaranteed to be positive.

Nor is it guaranteed to be random.

 

[Spoon]

The return value of rand isn't guaranteed to be positive.

What does "positive" mean? Is x positive if and only if x > 0?
Does that mean that 0 is neither positive nor negative?

For the record, the rand function computes a sequence of
pseudo-random integers in the range 0 to RAND_MAX.

 

[James Kuyper]

What does "positive" mean? Is x positive if and only if x > 0?
Does that mean that 0 is neither positive nor negative?

Correct.

 

[Richard Heathfield]

Spoon said:

What does "positive" mean?

Greater than zero.

Is x positive if and only if x > 0?
Yes.

Does that mean that 0 is neither positive nor negative?
Yes.

For the record, the rand function computes a sequence of
pseudo-random integers in the range 0 to RAND_MAX.

Yes.

 

[Johannes Bauer]

Greater than zero.


Yes.

The question if 0 is positive or not is one which has long been debated
my mathematicians around the world - and still is. Many are of the
opinion that it is useful to define it as positive, just as it is useful
to define 0^0 = 1 (although this is not as clear as it might seem).

The point is: It's a question a definition. Your answer is much too
dogmatic.

Greetings,
Johannes

 

[James Kuyper]

The question if 0 is positive or not is one which has long been debated
my mathematicians around the world - and still is. Many are of the
opinion that it is useful to define it as positive, just as it is useful
to define 0^0 = 1 (although this is not as clear as it might seem).

The point is: It's a question a definition. Your answer is much too
dogmatic.

There might be obscure discussions among mathematicians in which such a
definition is used, but I believe that in almost all contexts, the
overwhelming majority of the mathematically literate population consider
0 to be neither positive nor negative. I don't think it's excessively
dogmatic to insist on interpreting it that way in this context.

 

[Johannes Bauer]

There might be obscure discussions among mathematicians in which such a
definition is used, but I believe that in almost all contexts, the
overwhelming majority of the mathematically literate population consider
0 to be neither positive nor negative. I don't think it's excessively
dogmatic to insist on interpreting it that way in this context.

They are not obscure. Consider the work of Peano
(http://en.wikipedia.org/wiki/Giuseppe_Peano) which in his older works
state that the positive Integers start at 1, while at a later release
(Peano.G.: Formulaire de mathématiques 5 Bde. Turin, Bocca 1895-1908) he
states they start at zero.

It is *not* something that "almost all mathematicians" agree about, it
is primarily a question of usefulness. Both variants are common, it even
depends which university you're attending. Dogmatism are stupid, there
are good reasons why zero should be considered a positive integer and
there are also good reasons why it shouldn't. It's important to base
your decision on reason, not on "that's what I think everybody is doing".

Then again - in a trueley mathematic sense - almost all mathematicians
consider zero to be nonpositive. Almost all of them agree that zero is a
positive number, too. This is because "almost" in a mathematic sense
means "except for a finite number of exceptions"

Greetings,
Johannes