Contributed for hacktoberfest2022

geeks.cpp

@@ -0,0 +1,31 @@
+#include<iostream>
+int main()
+  {
+    int *a;
+    int n,d,i;
+    printf("array size");
+    scanf("%d",&n);
+    a = (int *)calloc(n, sizeof(int));
+    for(i=0;i<n;i++)
+    {
+        scanf("%d",&a[i]);
+    }
+    int l = sizeof(a)/sizeof(a[0]);
+    printf("enter rotations");
+    scanf("%d",&d);
+    int p = 1;
+    while (p <= d) {
+      int last = a[0];
+      for (int i = 0; i < n - 1; i++) {
+        a[i] = a[i + 1];
+      }
+      a[n - 1] = last;
+      p++;
+    }
+
+    printf("Array after Rotation :");
+    for (int i = 0; i < n; i++) {
+      printf("%d",a[i]);
+    }
+    return 0;
+  }

geeks3.cpp

@@ -0,0 +1,69 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+/*Prototype for utility functions */
+void printArray(int arr[], int size);
+void swap(int arr[], int fi, int si, int d);
+
+void leftRotate(int arr[], int d, int n)
+{
+  /* Return If number of elements to be rotated
+  is zero or equal to array size */
+  if(d == 0 || d == n)
+    return;
+  /* If number of elements to be rotated is more than array size*/
+  if(d > n)
+  d = d % n;
+  /*If number of elements to be rotated
+  is exactly half of array size */
+  if(n - d == d)
+  {
+    swap(arr, 0, n - d, d);
+    return;
+  }
+
+  /* If A is shorter*/    
+  if(d < n - d)
+  {
+    swap(arr, 0, n - d, d);
+    leftRotate(arr, d, n - d);  
+  }
+  else /* If B is shorter*/    
+  {
+    swap(arr, 0, d, n - d);
+    leftRotate(arr + n - d, 2 * d - n, d); /*This is tricky*/
+  }
+}
+
+/*UTILITY FUNCTIONS*/
+/* function to print an array */
+void printArray(int arr[], int size)
+{
+  int i;
+  for(i = 0; i < size; i++)
+    cout << arr[i] << " ";
+  cout << endl;
+}
+
+/*This function swaps d elements starting at index fi
+with d elements starting at index si */
+void swap(int arr[], int fi, int si, int d)
+{
+  int i, temp;
+  for(i = 0; i < d; i++)
+  {
+    temp = arr[fi + i];
+    arr[fi + i] = arr[si + i];
+    arr[si + i] = temp;
+  }
+}
+
+// Driver Code
+int main()
+{
+  int arr[] = {1, 2, 3, 4, 5, 6, 7};
+  leftRotate(arr, 2, 7);
+  printArray(arr, 7);
+  return 0;
+}
+