Question

How do I implement the following sorting methods with an int array in C++.
I need to create the implementation must be coded in C++:
1) Shell sort

2) Merge Sort

3) Quick Sort

4) Brick Sort or Gnome Sort

Answer 1

#include <iostream>
using namespace std;
void gnomesort(int ar[],int n){
int i=0,temp;
while (i < n)
{
if (i == 0 || ar[i - 1] <= ar[i])
i++;
else
{
temp = ar[i-1];
ar[i - 1] = ar[i];
ar[i] = temp;
i = i - 1;
}
}
}
void quicksort(int list[], int low, int high)
{
int pivot, i, j, temp;
if (low < high)
{
pivot = low;
i = low;
j = high;
while (i < j)
{
while (list[i] <= list[pivot] && i <= high)
{
i++;
}
while (list[j] > list[pivot] && j >= low)
{
j--;
}
if (i < j)
{
temp = list[i];
list[i] = list[j];
list[j] = temp;
}
}
temp = list[j];
list[j] = list[pivot];
list[pivot] = temp;
quicksort(list, low, j - 1);
quicksort(list, j + 1, high);
}
}
void merge(int *a, int low, int high, int mid)
{
int i, j, k, c[50];
i = low;
k = low;
j = mid + 1;
while (i <= mid && j <= high)
{
if (a[i] < a[j])
{
c[k] = a[i];
k++;
i++;
}
else
{
c[k] = a[j];
k++;
j++;
}
}
while (i <= mid)
{
c[k] = a[i];
k++;
i++;
}
while (j <= high)
{
c[k] = a[j];
k++;
j++;
}
for (i = low; i < k; i++)
{
a[i] = c[i];
}
}
void mergesort(int *a, int low, int high)
{
int mid;
if (low < high)
{
mid=(low+high)/2;
mergesort(a,low,mid);
mergesort(a,mid+1,high);
merge(a,low,high,mid);
}
return;
}

void print_ar (int ar[], int size)
{
for (int i = 0; i < size; ++i)
{
cout << ar[i] << " ";
}
cout << endl;
}

void shell_sort (int ar[], int size)
{
int j;

for (int gap = size / 2; gap > 0; gap /= 2)
{
for (int i = gap; i < size; ++i)
{
int temp = ar[i];
for (j = i; j >= gap && temp < ar[j - gap]; j -= gap)
{
ar[j] = ar[j - gap];
}
ar[j] = temp;
}
}
}

int main ()
{
int ar[] = {1, 4, 16, 30, 29, 18, 100, 2, 43, 1};

cout << "Intial Array : ";
print_ar (ar, 10);

shell_sort (ar, 10);

cout << "Sorted Array after shell sort: ";
print_ar (ar, 10);

int a[] = {1, 4, 16, 30, 29, 18, 100, 2, 43, 1};

cout << "Intial Array : ";
print_ar (a, 10);

gnomesort (a, 10);

cout << "Sorted Array after shell sort: ";
print_ar (a, 10);

int arr[] = {1, 4, 16, 30, 29, 18, 100, 2, 43, 1};

cout << "Intial Array : ";
print_ar (arr, 10);

mergesort (arr, 0,9);

cout << "Sorted Array after merge sort: ";
print_ar (arr, 10);

int arrr[] = {1, 4, 16, 30, 29, 18, 100, 2, 43, 1};

cout << "Intial Array : ";
print_ar (arrr, 10);

quicksort(arrr,0,9);

cout << "Sorted Array after quick sort: ";
print_ar (arrr, 10);
return 0;
}