Create quicksort.cpp

C++/quicksort.cpp

@@ -0,0 +1,64 @@
+#include <iostream>
+using namespace std;
+// Swap two elements - Utility function  
+void swap(int* a, int* b) 
+{ 
+    int t = *a; 
+    *a = *b; 
+    *b = t; 
+} 
+
+// partition the array using last element as pivot
+int partition (int arr[], int low, int high) 
+{ 
+    int pivot = arr[high];    // pivot 
+    int i = (low - 1);   
+
+    for (int j = low; j <= high- 1; j++) 
+    { 
+        //if current element is smaller than pivot, increment the low element
+        //swap elements at i and j
+        if (arr[j] <= pivot) 
+        { 
+            i++;    // increment index of smaller element 
+            swap(&arr[i], &arr[j]); 
+        } 
+    } 
+    swap(&arr[i + 1], &arr[high]); 
+    return (i + 1); 
+} 
+
+//quicksort algorithm
+void quickSort(int arr[], int low, int high) 
+{ 
+    if (low < high) 
+    { 
+        //partition the array 
+        int pivot = partition(arr, low, high); 
+
+        //sort the sub arrays independently 
+        quickSort(arr, low, pivot - 1); 
+        quickSort(arr, pivot + 1, high); 
+    } 
+} 
+
+void displayArray(int arr[], int size) 
+{ 
+    int i; 
+    for (i=0; i < size; i++) 
+        cout<<arr[i]<<"\t"; 
+
+} 
+
+int main() 
+{ 
+    int arr[] = {12,23,3,43,51,35,19,45}; 
+    int n = sizeof(arr)/sizeof(arr[0]); 
+    cout<<"Input array"<<endl;
+    displayArray(arr,n);
+    cout<<endl;
+    quickSort(arr, 0, n-1); 
+    cout<<"Array sorted with quick sort"<<endl; 
+    displayArray(arr,n); 
+    return 0; 
+}