The Two Directional Selection Sort Algorithm - C++ code

By Sergey Skudaev

Precondition:  The TwoDirectionSelSort accepts two parameters: unsorted array [] and integer size that is the size of the array.  

Post condition: Sorted array.

The function sorts the array in two directions. It checks if the current number is the smallest or the largest one. If it is the smallest, the number is moved to the front of the array.

If it is the largest, the number is moved to the end of the array. After each pass, the array becomes shorted by one number from the front and by one number from the end of the array

#include "stdafx.h"
#include <iostream>

using namespace std;

int* TwoDirectionSelSort ( int size, int array [] );
void exchange (int array[], int a, int b);


int main(int argc, char* argv[])
{

int array[10];
int i=0;

 while (i < 10)
{

cout<<"Please enter a number."<<endl;
cin>>array[i];
i++;

}
				cout<<"Unsorted array:"<<endl;
				for(int k=0; k<10;k++)
                cout<<array[k];
				cout<<endl;

 //call the sorting function
 int* arr=TwoDirectionSelSort(i,array);

				cout<<"Sorted array:"<<endl;
				for(int n=0; n<10;n++)
                cout<<arr[n];
				cout<<endl;

     int hold = 1;
     cin >> hold;

return 0;
 }








int* TwoDirectionSelSort ( int size, int array [] )
{
    int current = 0;
    bool sorted = false;
    int* pointer;
	pointer=array;

    while ((current < size-1) && (sorted == false))
    {
        int smallest = current;      // the first element of the array
        int largest = size - 1;        // the last element of the array
        int walker = current +1;
        sorted = true;


            if ( array [smallest] > array [largest] )
            {
                exchange ( array, smallest, largest );
                sorted = false;
            }
                        while( walker < size )
                        {
                            if ( array [walker] < array [smallest] )
                            {
                            exchange ( array, walker, smallest );
                            sorted = false;
                            }
                                    if ( array [walker] > array [largest] )
                                    {
                                    exchange( array, walker, largest);
                                    sorted = false;
                                     }
                                    walker = walker + 1;
                        }
                                    current = current + 1;
                                    size = size -1;
            }
	return pointer;
}

void exchange (int array[], int a, int b)
{
           int temp=array[a];
           array[a]=array[b];
           array[b]=temp;
}

Demo Java Applet

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