HELP with coding.....

This is a discussion on HELP with coding..... within the C Programming forums, part of the General Programming Boards category; hello everyone...I'm still learning c...I had to create a porgram to calculate the number of possible selections of choosing R ...

  1. #1
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    Question HELP with coding.....

    hello everyone...I'm still learning c...I had to create a porgram to calculate the number of possible selections of choosing R players from N. I have use the facotorial function..I have done the coding..there is till one error in it..If someone could help..plzzzz

    Code:
    void main()
    {
    	int n,r;
    	long int selection;
    	int factorial();
    
    	printf("\n Enter the N-number of players:");
    	scanf("%",&n);
    	printf("\n Enter the R-number of players you wish to select from %d players:",n);
    	scanf("%d",&r);
    
    	selection= (factorial(n))/ ((factorial(r))*(factorial(n-r)));
    
    	printf("\n The number of possible selections of %d players from %d players is %d",r,n,selection);
    
    
    
    
    }
    
    int factorial(int x)
    
    {
    	if (n<1)
    		return(1);
    	else
    		return(n*factorial(n-1));
    
    }

  2. #2
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    Describe the problem a bit better, please...

    Is it compiling but not running, running but not giving correct result, or not even compiling? If it's running with the wrong result, what are the data you enter?

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    Mats
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  3. #3
    and the hat of wrongness Salem's Avatar
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    > scanf("&#37;",&n);
    Are you forgetting something here?

    Also main returns int, not void.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    thanks for ur quick replies..ooops for the small errorss...

    Well I needed to kno if the way I treatred the question was well...

    If this way i would get the answer correctly...

    when I run it for the first time..after entering data for n..the compiler doesnt ask for entering R but goes directly to the answer..????

  5. #5
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    n in
    Code:
    }
    
    int factorial(int x)
    
    {
    	if (n<1)
    		return(1);
    	else
    		return(n*factorial(n-1));
    
    }
    is said to be undefined....

  6. #6
    and the hat of wrongness Salem's Avatar
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    Until you fix the first scanf, I can't see it doing anything but skip reading n.

    > is said to be undefined....
    Your parameter is x, yet you use n.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  7. #7
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    thanks..i spoted my mistake....

    Oh GOD............Its working.....................


    I managed to run it successfully....


    in int factorial[int x] should have been int factorial[int n]


    Thanks guys...sorrry for disturbing ya........ Thanks agai

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    If u guys dont mind... can I ask another question plzzzzzzzzzzzzz???? Its concerning another program... I just really cant understand how perform this condition...

    It says ask a question.. if answer is right pass to next...if it is wrong repeat question..if again wrong then give right answer.....


    what condition loop may i use??? If else, While, for or do..??? Plzz helpp

  9. #9
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    You can, realisticly, perform that as a for, while or do-while loop. The most natural choice is perhaps a for-loop, because you have a set number of "iterations" (two) that you should perform the task. But any of the loops can do this.

    You could also do it using if/else, but that would repeat the same bit of code, which for the purpose of this excercise seems "wrong".

    --
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    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  10. #10
    Fear the Reaper...
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    You don't need a loop for that at all. You just needed an if-else statement with another if-else statement nest in its else clause.
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  11. #11
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    Quote Originally Posted by Happy_Reaper View Post
    You don't need a loop for that at all. You just needed an if-else statement with another if-else statement nest in its else clause.
    Yes, but that's not "teaching how to use loops" - which I have a feeling is what the excercise is about - I could be wrong, it could be about "nested if-statements", in which case your solution is right - but this solution is very inflexible - if you want to ask 3 times, 4 times or 5 times, you need to (noticably) change the code. A loop solution is very easy to change the number of iterations that it does.

    --
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    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  12. #12
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    hmmmmmmmmmmmmmmmmmmmmmmmm.......well can any one write up abit of the code..I'll still cant get that in my head...
    P.s Do I need a counter here????

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    hmmm Guys...I'll give it a try...If Im still messed up..I'll get the coding here for u to help..

    Once again thanks a lot..dunno what I would have done If this forum wasnt here...

  14. #14
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    Yes, you will need SOME way of counting how many times you've done it - unless you build the "count" into the code as Happy_reaper suggests.

    I'd rather that you TRY to write something, post it here, and then we'll discuss how to "improve" and "fix" it. That way, you do the learning, we do the correcting - rather than you only learning "that if you ask someone else to do it, you get something".

    Of course, I could write something that you would get zero points for by your teacher - even if it works... Would you rather that I posted that?

    --
    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

  15. #15
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    ur right.....I'll try my best to start the coding a bit..n post it here..If ever Im completely stucK..please bear with me..Im still a newbie in this....

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