Question

#ifndef RADIXSORT
#define RADIXSORT

#include<vector>

// Function to get maximum value in array a[].
template <typename dataType>
int getmax(dataType a[], int n)
{
int max = a[0];
for (int x = 1; x < n; x++)
if (a[x] > max)
max = a[x];
return max;
}

// Function to do counting sort according to significant digits repesented by
// exp (where exp is 10^i).
template <typename dataType>
void CountSort(dataType a[], int n, int exp)
{
vector <int> result(n);
int i, count[10] = { 0 };

// Counting occurence of digits
for (i = 0; i < n; i++)
count[(a[i] / exp) % 10]++;

// Changing the position of count so that it appears at actual position in result.
for (i = 1; i < 10; i++)
count[i] += count[i - 1];

// Resultant output array
for (i = n - 1; i >= 0; i--)
{
result[count[(a[i] / exp) % 10] - 1] = a[i];
count[(a[i] / exp) % 10]--;
}
for (i = 0; i < n; i++)
a[i] = result[i];
}

// Radix Sort to sort a[] of given size.
template <typename dataType>
void radixSort(dataType a[], int n)
{
int exp, i;
i = getmax(a, n);
for (exp = 1; i / exp > 0; exp *= 10)
CountSort(a, n, exp);
}
#endif // RADIXSORT

I used the vector on vector <int> result(n). Is there anything that I can change within this code to make sure it works properly. C++ only.

Answer 1

If you have any doubts/errors, please give me comment...

#ifndef RADIXSORT

#define RADIXSORT

#include <vector>

// Function to get maximum value in array a[].

template <typename dataType>

int getmax(dataType a[], int n)

{

    int max = a[0];

    for (int x = 1; x < n; x++)

        if (a[x] > max)

            max = a[x];

    return max;

}

// Function to do counting sort according to significant digits repesented by

// exp (where exp is 10^i).

template <typename dataType>

void CountSort(dataType a[], int n, int exp)

{

    std::vector<dataType> result(n);

    int i, count[10] = {0};

    // Counting occurence of digits

    for (i = 0; i < n; i++)

        count[(a[i] / exp) % 10]++;

    // Changing the position of count so that it appears at actual position in result.

    for (i = 1; i < 10; i++)

        count[i] += count[i - 1];

    // Resultant output array

    for (i = n - 1; i >= 0; i--)

    {

        result[count[(a[i] / exp) % 10] - 1] = a[i];

        count[(a[i] / exp) % 10]--;

    }

    for (i = 0; i < n; i++)

        a[i] = result[i];

}

// Radix Sort to sort a[] of given size.

template <typename dataType>

void radixSort(dataType a[], int n)

{

    int exp, i;

    i = getmax(a, n);

    for (exp = 1; i / exp > 0; exp *= 10)

        CountSort(a, n, exp);

}

#endif // RADIXSORT

main.cpp

#include<iostream>

#include<vector>

#include "radix_sort.h"

using namespace std;

int main(){

    int arr[] = {27,12,72,36,37,29,26,22,97,86};

    radixSort(arr, 10);

    for(int i=0; i<10; i++){

        cout<<arr[i]<<endl;

    }

    return 0;

}