Restyle Added Quicksort in C++ fixes issue #12 . (#45)

* Added Quick sort algorithm in C++ .

* Custom array input added and file name corrected

* Restyled by astyle

* Restyled by clang-format

Co-authored-by: Roshan Prakash Raut <[email protected]>
Co-authored-by: Restyled.io <[email protected]>

Sorting/bucket_sort/quick_sort.cpp

@@ -0,0 +1,94 @@
+/*
+QUICK SORT ALGORITHM : 	TIME COMPLEXITY O(nlogn(n))
+
+*/
+
+#include <iostream>
+using namespace std;
+
+// note: call by address in swap function
+void swap(int *a, int *b) {
+  int t;
+  t = *a;
+  *a = *b;
+  *b = t;
+}
+
+// partition function which makes partition in array and return the partition
+// index
+int partition(int a[], int low, int high) {
+  // i is leftmost index and j is the rightmost index
+  int i = low, j = high;
+  int pivot = a[low];
+
+  do {
+    do {
+      i++;
+    } while (
+        a[i] <=
+        pivot); // note :condition is for continuation of loop ans not for stop
+
+    do {
+      j--;
+    } while (
+        a[j] >
+        pivot); // note: condition is for continuation of loop and not for stop
+
+    if (i < j)            // note: condition
+      swap(&a[i], &a[j]); // note:
+
+  } while (i < j); // note:condition
+
+  swap(&a[low], &a[j]); // note:
+
+  return j;
+}
+
+// Quick sort function
+void Quick_sort(int a[], int low, int high) {
+  int j; // j is partition index
+
+  // note: This condition for says that min two elements are required for quick
+  // sort
+  if (low < high) {
+    // index j is partition index
+    j = partition(a, low, high);
+
+    // left partition  // note: low to j is for left partition
+    Quick_sort(a, low, j);
+
+    // right partition    //note: j+1 to high is for right partition
+    Quick_sort(a, j + 1, high);
+  }
+}
+
+// main function
+int main() {
+
+  int n;
+
+  // Enter the number of elements in array
+  cin >> n;
+
+  int arr[n];
+
+  // input the custom array
+  for (int i = 0; i < n; i++) {
+    cin >> arr[i];
+  }
+
+  cout << "Before Quick Sort array is : ";
+  for (int i = 0; i < n; i++) {
+    cout << arr[i] << " ";
+  }
+  cout << endl;
+
+  // Quick sort
+  Quick_sort(arr, 0, n);
+
+  cout << "After Quick Sort array is : ";
+  for (int i = 0; i < n; i++) {
+    cout << arr[i] << " ";
+  }
+  cout << endl;
+}

Sorting/quick_sort/quick_sort.cpp

@@ -0,0 +1,94 @@
+/*
+QUICK SORT ALGORITHM : 	TIME COMPLEXITY O(nlogn(n))
+
+*/
+
+#include <iostream>
+using namespace std;
+
+// note: call by address in swap function
+void swap(int *a, int *b) {
+  int t;
+  t = *a;
+  *a = *b;
+  *b = t;
+}
+
+// partition function which makes partition in array and return the partition
+// index
+int partition(int a[], int low, int high) {
+  // i is leftmost index and j is the rightmost index
+  int i = low, j = high;
+  int pivot = a[low];
+
+  do {
+    do {
+      i++;
+    } while (
+        a[i] <=
+        pivot); // note :condition is for continuation of loop ans not for stop
+
+    do {
+      j--;
+    } while (
+        a[j] >
+        pivot); // note: condition is for continuation of loop and not for stop
+
+    if (i < j)            // note: condition
+      swap(&a[i], &a[j]); // note:
+
+  } while (i < j); // note:condition
+
+  swap(&a[low], &a[j]); // note:
+
+  return j;
+}
+
+// Quick sort function
+void Quick_sort(int a[], int low, int high) {
+  int j; // j is partition index
+
+  // note: This condition for says that min two elements are required for quick
+  // sort
+  if (low < high) {
+    // index j is partition index
+    j = partition(a, low, high);
+
+    // left partition  // note: low to j is for left partition
+    Quick_sort(a, low, j);
+
+    // right partition    //note: j+1 to high is for right partition
+    Quick_sort(a, j + 1, high);
+  }
+}
+
+// main function
+int main() {
+
+  int n;
+
+  // n - number of inputs
+  cin >> n;
+
+  int arr[n];
+
+  // input the custom array
+  for (int i = 0; i < n; i++) {
+    cin >> arr[i];
+  }
+
+  cout << "Before Quick Sort array is : ";
+  for (int i = 0; i < n; i++) {
+    cout << arr[i] << " ";
+  }
+  cout << endl;
+
+  // Quick sort
+  Quick_sort(arr, 0, n);
+
+  cout << "After Quick Sort array is : ";
+  for (int i = 0; i < n; i++) {
+    cout << arr[i] << " ";
+  }
+  cout << endl;
+}