From: Jeff Wood <jeff.darklight@...>
Date: 2005-11-12T14:05:30+09:00
Subject: Re: I rea......lly need your help ( C++ )

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Uhm,

2 things, you learn by figuring things out for yourself. And 2, the Ruby
list is for talking about programs & programming in Ruby.

Not to sound harsh, but you are much more likely to get a response in an ir=
c
#c++ chat room than spamming a mailing list about a completely different
programming language...

I wish you luck.

j.

On 11/11/05, ashmangat@yahoo.com <ashmangat@yahoo.com> wrote:
>
> Hey I am new, but I don't have time to intruduce myself yet.
> I am intro to C++
> and this is a programme I have to write.
> all the direction are here, It will be very nice of someone to figure
> this out.
> note: I only in intro C++ which is about to be finished by the next two
> weeks.
> The topic which I am on in my book is "POINTERS"
>
> Text from the book:
>
> Write a program that can be used to gather statistical data about the
> number
> of movies college students see in a month. The program should perform
> the
> following steps:
> Ask the user how many students were surveyed. An array of
> integers with this many elements should be dynamically allocated.
> Allow the user to enter the number of movies each student saw into the
> array.
> Calculate and display the average, median, and mode of the values
> entered.
> (Use the functions you wrote in problem 6 and 7 to calculate the median
> and mode.)
>
> Input Validation: Do not accept negative numbers for input.
>
>
> Additional Notes:
>
> Use the following skeleton for the main program:
>
> void main(void)
> {
> int *dyn_array;
> int mode, students;
> float avrg;
>
> do
> {
> cout << "How many students will you enter? ";
> cin >> students;
> }while ( students <=3D 0 );
>
> dyn_array =3D create_array( students );
> //this funtion creates a dynamic array
> //and is found in the book
> enter_data( dyn_array, students );
> //use 'pointer' notation in this function to
> //access array elements
> mode =3D get_mode( dyn_array, students );
> //check out pc6 for an explanation of 'mode'
> //median =3D median( dyn_array, students );
> //don't do median in this exercise
> avrg =3D average( dyn_array, students );
> //should be trivial
>
>
> cout << "The array is: ";
> showArray( dyn_array, students);
> //you should already have this function
> cout << endl;
> cout << "The Mode is " << mode << ".\n";
> cout << "The average is " << avrg << ".\n";
>
> delete [] dyn_array;
> return 0;
> }
>
> Some help (and requirements) for the mode function:
>
> 'mode' as explained in pc6: "In Statistics, the 'mode' of a set of
> value is the
> value, which occurs most often or with the greatest frequency".
>
> Note: Very important to completely understand the explanation below.
> Get
> on the discussion board if there is any confusion.
>
> The call:
> mode =3D get_mode(dyn_array, student);
>
> The function header:
> int get_mode(int *student_data, int num_students)
>
> get_mode should do the following:
>
> create an array 'frequency' of 1000 integers. 1000 is arbitrarily
> chosen as
> the absolute maximum of movies a college student could see in a week.
> This array
> will keep track of frequencies of weekly movie watching values.
>
> Intialize array 'frequency' elements to zeros (use a loop)
>
> Populate the 'frequency' array with the data (how many students see 1,
> 2, 3,
> etc. movies a week)
>
> The following algorithm is a useful method to easily increment random
> values:
>
> Run a loop on 'student_data' from 0 to 'num_students'.
>
> The content of 'student_data' array becomes the
> index of the 'frequency' array and the content of that 'frequency'
> array
> element gets incremented. Very important to understand this process.
>
> Here is a little animation help for
> the sentence content of 'student_data' array becomes the index of the
> 'frequency' array'.
>
> In subscript notation, it would look like this:
>
> frequency [ student_data[index] ] ++
>
> However, a requirement for the code above is to implement
> student_data[index]' in pointer notation and leave frequency[] in
> subscript
> notation.
>
> Example of processing the mode with 'frequency' and 'student_array':
>
> If, at the beginning, the frequency array contains:
>
> 0 0 0 0 0 0 ...
> and 'student_data' contains:
>
> 2 4 1 2 ...
>
> In the loop the first element '2' points to the third element (index 2)
> in the
> 'frequency' array and increments it. So now 'frequency' looks like
> this:
>
> 0 0 1 0 0 0 ...
>
> By the time the loop runs through all 4 elements of 'student_data',
> 'frequency'
> will look like this:
>
> 0 1 2 0 1 0 ...
>
> Notice that the 'frequency' array above now contains the mode: 2 movies
> a week
> (the third element, but index 2) contains the biggest number. Makes
> sense? If
> you aggree with the process described above, then you can write the
> program to
> accomplish it.
>
>
> After the 'frequency' array is updated with frequencies of all data,
> make a
> new loop with the 'frequency' array to pick out the largest value. Use
> the same
> function used in earlier assignment. It should look something like:
>
> for(i =3D 0; i < 1000; i++)
> {
> if(max < frequency[i])
> { max =3D frequency[i];
> maxi =3D i;
> }
> }
> return maxi -- remember that the index corresponds to the movies seen
> per week!
>
>
> Note: Do not worry about making the program handle bimodal values (mode
> having
> two values).
> Don't forget to block-comment every function definition. Example:
>
> //*******************************************
> // enter_data()
> // This function inputs data for all students
> // into dynimacally created array
> //*******************************************
>
>
>


--
"Remember. Understand. Believe. Yield! -> http://ruby-lang.org"

Jeff Wood

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