Standare deviation for discrete data

# Statistics with C++

//Program to calculate STANDARD DEVIATION for DISCRETE FREQUENCY DISTRIBUTION

#include<iostream.h>
#include<iomanip.h>
#include<conio.h>
#include<math.h>
const S=30;
class MSqdev
{
  public: float X[S],F[S],XM[S],SXM[S];
 float n,sqXM[S],FSXM[S],XF[S];
 float SDe;
  public: void Getdata();
 void MeanSQdevi();
 void show();
};

void MSqdev :: Getdata()
{
  cout<<"\nEnter total number of Data : ";
  cin>>n;
  cout<<"\nEnter Your Data : \n\n";
  for(int i=0;i<n;i++)
  {
    cout<<" X "<<i+1<<" : ";
    cin>>X[i];
  }
  cout<<"\nEnter frequencies for above data : \n\n";

  for(int j=0;j<n;j++)
  {
    cout<<"Frequency for "<<X[j]<<" Calls : ";
    cin>>F[j];
  }
}

void MSqdev :: MeanSQdevi()
{
  float SXF = 0;
  float SF = 0,Sfxm=0;
  float Mean;

  for(int i=0;i<n;i++)
  {
    SF += F[i];
    XF[i] = (F[i]*X[i]);
    SXF += XF[i];
  }

  Mean= SXF/SF;

    for( i=0;i<n;i++)
  {

     XM[i]= (X[i]-Mean);
     SXM[i]=(XM[i]*XM[i]);
     FSXM[i]=(F[i]*SXM[i]);
    Sfxm+=FSXM[i];
  }

  SDe=sqrt(Sfxm/SF);

}

void MSqdev :: show()
{
  cout<<"\n\n*** YOUR DATA IS AS FOLLOWS: ***\n\n";
  cout<<"\nX \t F \t FX \t |X-A| \t (X-A)2 \t F* (X-A)2\t\n";
  cout<<"\n\n-------------------------------------------------\n";
 for(int i=0;i<n;i++)
  {
      cout<<" "<<X[i]<<"\t"<<F[i]<<"\t"<<XF[i]<<"\t"<<setprecision(3)<<XM[i]<<"\t"<<SXM[i]<<"\t"      <<FSXM[i]<<"\n";
  }
  cout<<"\n\n---------------------------------------------------\n";
  cout<<"\n\nSTANDARD DEVIATION FOR YOUR DATA = "<<setprecision(3) <<SDe;
}

void main()
{
  MSqdev M;
  clrscr();
  M.Getdata();
  clrscr();
  M.MeanSQdevi();
  M.show();
  getch();

}

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Out Put :

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* Please comment if you find any error in the code or if it required corrections .

Happy Coding !