Adding Implementation of selection sort

Program's_Contributed_By_Contributors/C++/Radix_Sort.cpp

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+// C++ implementation of Radix Sort
+
+#include <iostream>
+using namespace std;
+
+// A utility function to get maximum value in arr[]
+int getMax(int arr[], int n)
+{
+	int mx = arr[0];
+	for (int i = 1; i < n; i++)
+		if (arr[i] > mx)
+			mx = arr[i];
+	return mx;
+}
+
+// A function to do counting sort of arr[] according to
+// the digit represented by exp.
+void countSort(int arr[], int n, int exp)
+{
+	int output[n]; // output array
+	int i, count[10] = { 0 };
+
+	// Store count of occurrences in count[]
+	for (i = 0; i < n; i++)
+		count[(arr[i] / exp) % 10]++;
+
+	// Change count[i] so that count[i] now contains actual
+	// position of this digit in output[]
+	for (i = 1; i < 10; i++)
+		count[i] += count[i - 1];
+
+	// Build the output array
+	for (i = n - 1; i >= 0; i--) {
+		output[count[(arr[i] / exp) % 10] - 1] = arr[i];
+		count[(arr[i] / exp) % 10]--;
+	}
+
+	// Copy the output array to arr[], so that arr[] now
+	// contains sorted numbers according to current digit
+	for (i = 0; i < n; i++)
+		arr[i] = output[i];
+}
+
+// The main function to that sorts arr[] of size n using
+// Radix Sort
+void radixsort(int arr[], int n)
+{
+	// Find the maximum number to know number of digits
+	int m = getMax(arr, n);
+
+	// Do counting sort for every digit. Note that instead
+	// of passing digit number, exp is passed. exp is 10^i
+	// where i is current digit number
+	for (int exp = 1; m / exp > 0; exp *= 10)
+		countSort(arr, n, exp);
+}
+
+// A utility function to print an array
+void print(int arr[], int n)
+{
+	for (int i = 0; i < n; i++)
+		cout << arr[i] << " ";
+}
+
+// Driver Code
+int main()
+{
+	int arr[] = { 170, 45, 75, 90, 802, 24, 2, 66 };
+	int n = sizeof(arr) / sizeof(arr[0]);
+
+	// Function Call
+	radixsort(arr, n);
+	print(arr, n);
+	return 0;
+}

Program's_Contributed_By_Contributors/C++/heap_sort.cpp

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+// C++ program for implementation of Heap Sort
+
+#include <iostream>
+using namespace std;
+
+// To heapify a subtree rooted with node i
+// which is an index in arr[].
+// n is size of heap
+void heapify(int arr[], int N, int i)
+{
+
+    // Initialize largest as root
+    int largest = i;
+
+    // left = 2*i + 1
+    int l = 2 * i + 1;
+
+    // right = 2*i + 2
+    int r = 2 * i + 2;
+
+    // If left child is larger than root
+    if (l < N && arr[l] > arr[largest])
+        largest = l;
+
+    // If right child is larger than largest
+    // so far
+    if (r < N && arr[r] > arr[largest])
+        largest = r;
+
+    // If largest is not root
+    if (largest != i) {
+        swap(arr[i], arr[largest]);
+
+        // Recursively heapify the affected
+        // sub-tree
+        heapify(arr, N, largest);
+    }
+}
+
+// Main function to do heap sort
+void heapSort(int arr[], int N)
+{
+
+    // Build heap (rearrange array)
+    for (int i = N / 2 - 1; i >= 0; i--)
+        heapify(arr, N, i);
+
+    // One by one extract an element
+    // from heap
+    for (int i = N - 1; i > 0; i--) {
+
+        // Move current root to end
+        swap(arr[0], arr[i]);
+
+        // call max heapify on the reduced heap
+        heapify(arr, i, 0);
+    }
+}
+
+// A utility function to print array of size n
+void printArray(int arr[], int N)
+{
+    for (int i = 0; i < N; ++i)
+        cout << arr[i] << " ";
+    cout << "\n";
+}
+
+// Driver's code
+int main()
+{
+    int arr[] = { 12, 11, 13, 5, 6, 7 };
+    int N = sizeof(arr) / sizeof(arr[0]);
+
+    // Function call
+    heapSort(arr, N);
+
+    cout << "Sorted array is \n";
+    printArray(arr, N);
+}

Program's_Contributed_By_Contributors/C++/selection_sort.cpp

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+// C++ program for implementation of
+// selection sort
+#include <bits/stdc++.h>
+using namespace std;
+
+//Swap function
+void swap(int *xp, int *yp)
+{
+	int temp = *xp;
+	*xp = *yp;
+	*yp = temp;
+}
+
+void selectionSort(int arr[], int n)
+{
+	int i, j, min_idx;
+
+	// One by one move boundary of
+	// unsorted subarray
+	for (i = 0; i < n-1; i++)
+	{
+
+		// Find the minimum element in
+		// unsorted array
+		min_idx = i;
+		for (j = i+1; j < n; j++)
+		if (arr[j] < arr[min_idx])
+			min_idx = j;
+
+		// Swap the found minimum element
+		// with the first element
+		if(min_idx!=i)
+			swap(&arr[min_idx], &arr[i]);
+	}
+}
+
+//Function to print an array
+void printArray(int arr[], int size)
+{
+	int i;
+	for (i=0; i < size; i++)
+		cout << arr[i] << " ";
+	cout << endl;
+}
+
+// Driver program to test above functions
+int main()
+{
+	int arr[] = {64, 25, 12, 22, 11};
+	int n = sizeof(arr)/sizeof(arr[0]);
+	selectionSort(arr, n);
+	cout << "Sorted array: \n";
+	printArray(arr, n);
+	return 0;
+}