shell sort

// ShellSort.cpp : Defines the entry point for the console application.

//

 

#include "stdafx.h"

#include <iostream>

 

void ShellSort(int* a, int iLen);

void PrintArray(int a[], int iLen);

 

int _tmain(int argc, _TCHAR* argv[])

{

    int arrayToSort[] = {20, 7, 3, 4, 25, 15, 29, 12, 4, 1};

    int n = sizeof(arrayToSort)/sizeof(int);

    PrintArray(arrayToSort, n);

    ShellSort(arrayToSort, n);

    PrintArray(arrayToSort, n);

    return 0;

}

 

void ShellSort(int* a, int iLen)

{

    if(a==NULL)

       return;

    if(iLen<=0)

       return;

    for(int increament=iLen/2;increament>=1;increament--)

    {

       for(int startIndex = 0; startIndex<increament;startIndex++)

       {

           int directSortIndex = startIndex + increament;

           while(directSortIndex<iLen)

           {

              int temp = a[directSortIndex];

              int innerIndex = directSortIndex - increament;

              while(innerIndex>=0&&temp<a[innerIndex])

              {

                  a[innerIndex+increament]=a[innerIndex];

                  innerIndex-=increament;

              }

              a[innerIndex+increament] = temp;

              directSortIndex += increament;

           }

       }

    }

}

 

void PrintArray(int a[], int iLen)

{

    for(int i=1; i< iLen; i++)

    {

       std::cout<<a[i]<<' ';

    }

    std::cout<<std::endl;

}