[C] How to shorten this program?

milky · 11-07-2009, 07:09 AM

Hi!

I'd like you to take a look at this code and tell me what should i do to make this shorter. This program count binomial coefficient. Thanks for all answers.

Code:

#include "stdio.h"
          
int main()
{
    int k,n,i,w;
    while (scanf("%d%d",&n,&k)==2)
    {
        if(k>n/2)
        k=n-k;
        for(w=i=1;i<=k;i++)
        w=w*(n++-i)/i;
        printf("%d\n",w);
    }
}

I think that

Code:

w=w*(n++-i)/i;

might be write shorter, but i can't figure it out.

P.s. Sorry for my English...

quzah · 11-07-2009, 07:28 AM

Swap your if for this:

Code:

k=k>n/2?n-k:k;

Quzah.

milky · 11-07-2009, 07:42 AM

Ok, thanks, is there anything else to do?

Brain_Child · 11-07-2009, 07:54 AM

Code:

    while (scanf("%d%d",&n,&k)==2)
    {

goes to

Code:

    while (scanf("%d%d",&n,&k)==2) {

why do you want to make it shorter?

it already looks cryptic with its 1 letter variable names and complete lack of spacing.

I compiled it and I dont think it works

5C3 = 5!/3!2! = 5*4/2 = 10
but your program returns 8

what algorithm are you using to calculate the coefficient?

Dino · 11-07-2009, 07:56 AM

w=w*(n++-i)/i;

can go to

w*=(n++-i)/i;

Dino · 11-07-2009, 07:59 AM

Code:

#include "stdio.h"
          
int main()
{
    int k,n,i,w;
    while (scanf("%d%d",&n,&k)==2) for(k=k>n/2?n-k:k,w=i=1;i<=k;w*=(n++-i)/i,printf("%d\n",w),i++) ;
}

Dino · 11-07-2009, 08:15 AM

Here's my final version.

Code:

#include <stdio.h>
int main()
{
	int k,n,i,w;
	while (scanf("%d%d",&n,&k)==2) for(k=k>n/2?n-k:k,w=i=1;i<=k;w*=(n++-i)/i++,printf("%d\n",w)) ;
	return 0;
}

Subsonics · 11-07-2009, 08:19 AM

Code:

#include <stdio.h>
int main(){int k,n,i,w;while(scanf("%d%d",&n,&k)==2)for(k=k>n/2?n-k:k,w=i=1;i<=k;i++,w*=(n++-i)/i,printf("%d\n",w));return 0;}

milky · 11-07-2009, 08:24 AM

Thanks @Dino, but it change my program, and doesn't work properly.

Subsonics · 11-07-2009, 08:25 AM

But what is the purpose of making the program cryptic and hard to read?

milky · 11-07-2009, 08:27 AM

I have to do this program using as less as i can chars.

Dino · 11-07-2009, 08:30 AM

Quote:

Originally Posted by milky

Thanks @Dino, but it change my program, and doesn't work properly.

Then it's worthless. (Did you run the version before or after my edit? Before the edit, I was incrementing i in the wrong spot.)

milky · 11-07-2009, 08:32 AM

I run your latest version and it also change my program:/ Maybe there is another, shorter algorithm to count binomial coefficient?

Dino · 11-07-2009, 10:44 AM

It might be good to start with the proper formula in the first place: Binomial coefficient - Wikipedia, the free encyclopedia

11-07-2009, 07:09 AM	#1
milky Registered User Join Date: Nov 2009 Posts: 13	[C] How to shorten this program? Hi! I'd like you to take a look at this code and tell me what should i do to make this shorter. This program count binomial coefficient. Thanks for all answers. Code: #include "stdio.h" int main() { int k,n,i,w; while (scanf("%d%d",&n,&k)==2) { if(k>n/2) k=n-k; for(w=i=1;i<=k;i++) w=w(n++-i)/i; printf("%d\n",w); } } I think that Code: w=w(n++-i)/i; might be write shorter, but i can't figure it out. P.s. Sorry for my English...
milky is offline

11-07-2009, 07:28 AM	#2
quzah +++ OK NO CARRIER Join Date: Oct 2001 Posts: 10,258	Swap your if for this: Code: k=k>n/2?n-k:k; Quzah. __________________ Hundreds of thousands of dipshits can't be wrong. Are you up for the suck?
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11-07-2009, 07:42 AM	#3
milky Registered User Join Date: Nov 2009 Posts: 13	Ok, thanks, is there anything else to do?
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11-07-2009, 07:54 AM	#4
Brain_Child Registered User Join Date: Feb 2009 Posts: 35	Code: while (scanf("%d%d",&n,&k)==2) { goes to Code: while (scanf("%d%d",&n,&k)==2) { why do you want to make it shorter? it already looks cryptic with its 1 letter variable names and complete lack of spacing. I compiled it and I dont think it works 5C3 = 5!/3!2! = 5*4/2 = 10 but your program returns 8 what algorithm are you using to calculate the coefficient?
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11-07-2009, 07:56 AM	#5
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 1,929	w=w(n++-i)/i; can go to w=(n++-i)/i; __________________ Mac and Windows cross platform programmer. Ruby lover. Memorable Quotes From Recent Posts: I can't remember.
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11-07-2009, 07:59 AM	#6
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 1,929	Code: #include "stdio.h" int main() { int k,n,i,w; while (scanf("%d%d",&n,&k)==2) for(k=k>n/2?n-k:k,w=i=1;i<=k;w=(n++-i)/i,printf("%d\n",w),i++) ; } __________________ Mac and Windows cross platform programmer. Ruby lover. Memorable Quotes From Recent Posts: I can't remember. Last edited by Dino; 11-07-2009 at 08:12 AM. Reason: moved i++ to end*
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11-07-2009, 08:15 AM	#7
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 1,929	Here's my final version. Code: #include <stdio.h> int main() { int k,n,i,w; while (scanf("%d%d",&n,&k)==2) for(k=k>n/2?n-k:k,w=i=1;i<=k;w*=(n++-i)/i++,printf("%d\n",w)) ; return 0; } __________________ Mac and Windows cross platform programmer. Ruby lover. Memorable Quotes From Recent Posts: I can't remember.
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11-07-2009, 08:19 AM	#8
Subsonics Registered User Join Date: Jan 2009 Posts: 151	Code: #include <stdio.h> int main(){int k,n,i,w;while(scanf("%d%d",&n,&k)==2)for(k=k>n/2?n-k:k,w=i=1;i<=k;i++,w*=(n++-i)/i,printf("%d\n",w));return 0;}
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11-07-2009, 08:24 AM	#9
milky Registered User Join Date: Nov 2009 Posts: 13	Thanks @Dino, but it change my program, and doesn't work properly.
milky is offline

11-07-2009, 08:25 AM	#10
Subsonics Registered User Join Date: Jan 2009 Posts: 151	But what is the purpose of making the program cryptic and hard to read?
Subsonics is offline

11-07-2009, 08:27 AM	#11
milky Registered User Join Date: Nov 2009 Posts: 13	I have to do this program using as less as i can chars.
milky is offline

11-07-2009, 08:32 AM	#13
milky Registered User Join Date: Nov 2009 Posts: 13	I run your latest version and it also change my program:/ Maybe there is another, shorter algorithm to count binomial coefficient?
milky is offline

11-07-2009, 10:44 AM	#14
Dino Jack of many languages Join Date: Nov 2007 Location: Katy, Texas Posts: 1,929	It might be good to start with the proper formula in the first place: Binomial coefficient - Wikipedia, the free encyclopedia __________________ Mac and Windows cross platform programmer. Ruby lover. Memorable Quotes From Recent Posts: I can't remember.
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