C / C++ / MFC

8-Aug-06 10:47

I am havin problems doing this c++ project.Its in regards to whether i can use one main class (e.g.main.cpp) or have to use a few classes.I am also a bit weak when it comes to c++ as java is my main language so any hints on the code or how to go about doing this would be great.The basic idea is :
Create a class called DataSet that stores a vector of floating-point values. Give this vector an initial size of zero, and use the push_back operation to add new elements.

The DataSet class should have a public member function for each of the operations described above, as well as a member function that adds an element to the vector.

I have to get the MEAN,MEDIAN and Standard Deviation.

I would very much appreciate if you could help me asap as I am desperately stuck.

PLEASE HELP ASAP IF U CAN

Thanks in advance,

klck2000

David Crow8-Aug-06 10:51

8-Aug-06 10:51

So what part is troubling you?

Creating a class

Adding a vector member

Initializing member variables

Adding to a vector

Creating other methods

Reading from a file

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

klck20008-Aug-06 10:58

8-Aug-06 10:58

tell you the truth,im having a problem with everything,i dont know where to start.i just dont know how to do it,iv tried but get nothing but errors.can you help??heres my main class:

#include <iostream>

//#include "main.h"

using namespace std;

#include "main.h"

int main(){

Calcs calcs("input.dat");

cout << "Mean is " << calcs.findMeanHeight() << "\n";

cout << "Standard deviation in height is " << calcs.findStandardDeviation() << "\n";

heres my calcs class to get the mean etc:

#include <fstream>
#include <cmath>
using namespace std;

#include "calcs.h"

Calcs:: Calcs(string filename){
ifstream ifile("input.dat");
/*ifile >> _dimension;
for (int i=0; i<_dimension; i++){
for (int j=0; j<_dimension; j++)
ifile >> _heights[i][j];
}
}

void Calcs::print(ostream& s) const {
for (int i=0; i<_dimension; i++){
for (int j=0; j<_dimension; j++)
s << _heights[i][j] << " ";
s << "\n";
}
*/
}

double Calcs::findMeanHeight() const {
double runningMean=0;
for (int i=0; i<_dimension; i++)
for (int j=0; j<_dimension; j++)
runningMean+=_heights[i][j]/(pow(_dimension,2.0));
return runningMean;
}

double Calcs::findStandardDeviation() const{
// return standard deviation of heights
double squareOfMeans = pow(findMeanHeight(),2.0);
return sqrt(meanOfSquares()-squareOfMeans);
}
}
}
}

double Calcs::meanOfSquares() const{
double runningMean=0;
for (int i=0; i<_dimension; i++)
for (int j=0; j<_dimension; j++)
runningMean+=pow(_heights[i][j],2.0)/pow(_dimension,2.0);
return runningMean;
}
PLEASE HELP!!

klck2000

David Crow8-Aug-06 11:08

8-Aug-06 11:08

klck2000 wrote:
,i dont know where to start.

It looks as though you have indeed started, and are well on your way.

klck2000 wrote:
iv tried but get nothing but errors.

What errors?

On a side note, you might want to update your post so that it is more readable (you'll get tons more help if folks don't have to squint their eyes and turn their head sideways to make sense of it all). Use the <pre> tags to surround the code and make sure the angle brackets are formatted correctly. The Preview button helps in this capacity.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

klck20008-Aug-06 11:16

Re: c++ Project help asap [modified]

8-Aug-06 11:16

ok sorry, im only fairly new at this.the project seems pretty basic but I just cannot do this at all.Could you give me the code or an idea on how to do this even,which would be a huge help:
Create a class called DataSet that stores a vector of floating-point values. Give this vector an initial size of zero, and use the push_back operation to add new elements

I just cannot get my head around this.From the input file I have to get the Mean,Median and standard deviation.The code I have used which I took from another c++ project I have done,is incorrect i think

thanks,

klck2000

markkuk8-Aug-06 11:40

markkuk

8-Aug-06 11:40

vector is a standard C++ container[^]. Its initial size is zero by default.

klck20008-Aug-06 11:47

8-Aug-06 11:47

Thanks,

I just pasted that from my project overview.By any chance would you be able to help me as I am desperate at this stage.I dont know where to start in regards to the code or what code to use??

klck2000

David Crow9-Aug-06 3:08

9-Aug-06 3:08

klck2000 wrote:
Could you give me...an idea on how to do this even...

Here is one idea:

class DataSet
{
public:
    DataSet() { }
 
    void Add( const double dHeight )
    {
        m_vecHeights.push_back(dHeight);
    }
 
    double Mean( void ) const { }
 
    double Median( void ) const { }
 
    double StdDev( void ) const { }
 
private:
    vector<double> m_vecHeights;
};
 
void main( void )
{
    DataSet ds;
}

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

klck20009-Aug-06 3:33

9-Aug-06 3:33

thanks very much,i tried something like that lastnight though id to use floating point values so used

class DataSet
{
private:
float Vector[200]; //Holds the floating values
int Number_of_Elements; //Holds the number of elemets -1
void Sort_Vector(); //Sorts the vector to calculate the median value
public:
DataSet(); //Constructor of the class
~DataSet(); //Destructor of the class
void Add_Element(float float_value); //Add an element into the vector
float Calculate_Mean();
float Calculate_Median();
float Calculate_Standard_Deviation();
};

how do you think that looks??

thanks,
karl

klck2000

David Crow9-Aug-06 4:55

9-Aug-06 4:55

klck2000 wrote:
float Vector[200]; //Holds the floating values

One of your requirements was to use the push_back() method to add items to the vector. What you have does not satisfy that requirement.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

klck20009-Aug-06 5:00

9-Aug-06 5:00

i cannot use the push_back method,i was having problems with understanding it.Any simple code suggestions??

klck2000

David Crow9-Aug-06 5:06

9-Aug-06 5:06

klck2000 wrote:
Any simple code suggestions??

See here.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

klck20009-Aug-06 5:10

9-Aug-06 5:10

many thanks

klck2000

David Crow6-Oct-06 10:01