Shell Sort

/*********************************************************

-> This C++ program is to perform Shell sort.

-> This program works in microsoft vc++ 6.0 environment.

-> The numbers are sorted in increasing order.

**********************************************************/

#include<iostream.h>

class sorting
{
private:
 double *array;
 int n;
public:
 void input();
 void shellsort();
 void output();
 void swap(double& g,double& f);
};

void sorting::input()
{
 cout<<”****************************************************\n”
  <<”This program sorts numbers in increasing order”
  <<”\n\t\tusing shell sort technique\n”
  <<”****************************************************\n”;

 cout<<”Enter how many numbers you are going to enter for sorting ::”;
 cin>>n;
 array=new double[n+1];
 cout<<”Now enter your elements ::\n”;
 for(int i=0;i<n;i++)
  cin>>array[i];
}

void sorting::swap(double &f,double &g)
{
 double temp;
 temp=f;
 f=g;
 g=temp;
}

void sorting::shellsort()
{
     int i,j,inc=3;
     double temp;
     while(inc>0)
     {
          for(i=0;i<n;i++)
          {
                   j=i;
                   temp=array[i];
                   while((j>=inc)&&array[j-inc]>temp)
                   {
                        array[j]=array[j-inc];
                        j=j-inc;
                   }
                   array[j]=temp;
          }
          if(inc/2!=0)
           inc=inc/2;
          else if(inc==1)
           inc=0;
          else
           inc=1;
     }
}

void sorting::output()
{
 cout<<”Now the sorted numbers are ::\n”;
 for(int i=0;i<n;i++)
  cout<<array[i]<<’\t’;
 cout<<endl;
}

int main()
{
 sorting obj;
 obj.input();
 obj.shellsort();
 obj.output();
 return 0;
}
/*********************************************************************

SAMPLE OUTPUT ::

****************************************************
This program sorts numbers in increasing order
                using shell sort technique
****************************************************
Enter how many numbers you are going to enter for sorting ::7
Now enter your elements ::
1.7
1.6
1.5
1.4
1.3
1.2
1.1
Now the sorted numbers are ::
1.1     1.2     1.3     1.4     1.5     1.6     1.7
Press any key to continue

***********************************************************************/