### old

#### Program to implement radix sort.

``` ```
#include < iostream >

// Get maximum value from array.
int getMax(int arr[], int n)
{
int max = arr[0];
for (int i = 1; i < n; i++)
if (arr[i] > max)
max = arr[i];
return max;
}

// Count sort of arr[].
void countSort(int arr[], int n, int exp)
{
// Count[i] array will be counting the number of array values having that 'i' digit at their (exp)th place.
int output[n], i, count[10] = {0};

// Count the number of times each digit occurred at (exp)th place in every input.
for (i = 0; i < n; i++)
count[(arr[i] / exp) % 10]++;

// Calculating their cumulative count.
for (i = 1; i < 10; i++)
count[i] += count[i-1];

// Inserting values according to the digit '(arr[i] / exp) % 10' fetched into count[(arr[i] / exp) % 10].
for (i = n - 1; i >= 0; i--)
{
output[count[(arr[i] / exp) % 10] - 1] = arr[i];
count[(arr[i] / exp) % 10]--;
}

// Assigning the result to the arr pointer of main().
for (i = 0; i < n; i++)
arr[i] = output[i];
}

// Sort arr[] of size n using Radix Sort.
{
int exp, m;
m = getMax(arr, n);

// Calling countSort() for digit at (exp)th place in every input.
for (exp = 1; m/exp > 0; exp *= 10)
countSort(arr, n, exp);
}

int main()
{
int n, i;
cout<<"\nEnter the number of data element to be sorted: ";
cin>>n;

int arr[n];
for(i = 0; i < n; i++)
{
cout<<   "Enter element "   <<   i+1   <<  ": ";
cin >> arr[i];
}