C++ Programming Code Examples

/* Program to Check if a Given Binary Tree is an AVL Tree or Not This is a C++ Program to check if BST is AVL. An AVL tree is a self-balancing binary search tree. It was the first such data structure to be invented. In an AVL tree, the heights of the two child subtrees of any node differ by at most one; if at any time they differ by more than one, rebalancing is done to restore this property. Lookup, insertion, and deletion all take O(log n) time in both the average and worst cases, where n is the number of nodes in the tree prior to the operation. Insertions and deletions may require the tree to be rebalanced by one or more tree rotations. A tree is AVL if and only if it is Binary Search Tree and is Balanced. */ #include <iostream> #include <cstdlib> using namespace std; /* Class SBBSTNode */ class SBBSTNode { public: int height, data; SBBSTNode *left, *right; /* Constructor */ SBBSTNode() { left = NULL; right = NULL; data = 0; height = 0; } /* Constructor */ SBBSTNode(int n) { left = NULL; right = NULL; data = n; height = 0; } }; /* Class SelfBalancingBinarySearchTree */ class SelfBalancingBinarySearchTree { private: SBBSTNode *root; public: /* Constructor */ SelfBalancingBinarySearchTree() { root = NULL; } /* Function to check if tree is empty */ bool isEmpty() { return root == NULL; } /* Make the tree logically empty */ void makeEmpty() { root = NULL; } /* Function to insert data */ void insert(int data) { root = insert(data, root); } /* Function to get height of node */ int height(SBBSTNode *t) { return t == NULL ? -1 : t->height; } /* Function to max of left/right node */ int max(int lhs, int rhs) { return lhs > rhs ? lhs : rhs; } /* Function to insert data recursively */ SBBSTNode *insert(int x, SBBSTNode *t) { if (t == NULL) t = new SBBSTNode(x); else if (x < t->data) { t->left = insert(x, t->left); if (height(t->left) - height(t->right) == 2) if (x < t->left->data) t = rotateWithLeftChild(t); else t = doubleWithLeftChild(t); } else if (x > t->data) { t->right = insert(x, t->right); if (height(t->right) - height(t->left) == 2) if (x > t->right->data) t = rotateWithRightChild(t); else t = doubleWithRightChild(t); } t->height = max(height(t->left), height(t->right)) + 1; return t; } /* Rotate binary tree node with left child */ SBBSTNode *rotateWithLeftChild(SBBSTNode* k2) { SBBSTNode *k1 = k2->left; k2->left = k1->right; k1->right = k2; k2->height = max(height(k2->left), height(k2->right)) + 1; k1->height = max(height(k1->left), k2->height) + 1; return k1; } /* Rotate binary tree node with right child */ SBBSTNode *rotateWithRightChild(SBBSTNode *k1) { SBBSTNode *k2 = k1->right; k1->right = k2->left; k2->left = k1; k1->height = max(height(k1->left), height(k1->right)) + 1; k2->height = max(height(k2->right), k1->height) + 1; return k2; } /* Double rotate binary tree node: first left child with its right child; then node k3 with new left child */ SBBSTNode *doubleWithLeftChild(SBBSTNode *k3) { k3->left = rotateWithRightChild(k3->left); return rotateWithLeftChild(k3); } /* Double rotate binary tree node: first right child with its left child; then node k1 with new right child */ SBBSTNode *doubleWithRightChild(SBBSTNode *k1) { k1->right = rotateWithLeftChild(k1->right); return rotateWithRightChild(k1); } /* Functions to count number of nodes */ int countNodes() { return countNodes(root); } int countNodes(SBBSTNode *r) { if (r == NULL) return 0; else { int l = 1; l += countNodes(r->left); l += countNodes(r->right); return l; } } /* Functions to search for an element */ bool search(int val) { return search(root, val); } bool search(SBBSTNode *r, int val) { bool found = false; while ((r != NULL) && !found) { int rval = r->data; if (val < rval) r = r->left; else if (val > rval) r = r->right; else { found = true; break; } found = search(r, val); } return found; } /* Function for inorder traversal */ void inorder() { inorder(root); } void inorder(SBBSTNode *r) { if (r != NULL) { inorder(r->left); cout << r->data << " "; inorder(r->right); } } /* Function for preorder traversal */ void preorder() { preorder(root); } void preorder(SBBSTNode *r) { if (r != NULL) { cout << r->data << " "; preorder(r->left); preorder(r->right); } } /* Function for postorder traversal */ void postorder() { postorder(root); } void postorder(SBBSTNode *r) { if (r != NULL) { postorder(r->left); postorder(r->right); cout << r->data << " "; } } }; int main() { SelfBalancingBinarySearchTree sbbst; cout << "SelfBalancingBinarySearchTree Test\n"; int val; char ch; /* Perform tree operations */ do { cout << "\nSelfBalancingBinarySearchTree Operations\n"; cout << "1. Insert " << endl; cout << "2. Count nodes" << endl; cout << "3. Search" << endl; cout << "4. Check empty" << endl; cout << "5. Make empty" << endl; int choice; cout << "Enter your Choice: "; cin >> choice; switch (choice) { case 1: cout << "Enter integer element to insert: "; cin >> val; sbbst.insert(val); break; case 2: cout << "Nodes = " << sbbst.countNodes() << endl; break; case 3: cout << "Enter integer element to search: "; cin >> val; if (sbbst.search(val)) cout << val << " found in the tree" << endl; else cout << val << " not found" << endl; break; case 4: cout << "Empty status = "; if (sbbst.isEmpty()) cout << "Tree is empty" << endl; else cout << "Tree is non - empty" << endl; break; case 5: cout << "\nTree cleared\n"; sbbst.makeEmpty(); break; default: cout << "Wrong Entry \n "; break; } /* Display tree*/ cout << "\nPost order : "; sbbst.postorder(); cout << "\nPre order : "; sbbst.preorder(); cout << "\nIn order : "; sbbst.inorder(); cout << "\nDo you want to continue (Type y or n): "; cin >> ch; } while (ch == 'Y' || ch == 'y'); return 0; }

/* using #include directive in C language */ #include <stdio.h> int main() { /* * C standard library printf function * defined in the stdio.h header file */ printf("I love you Clementine"); printf("I love you so much"); printf("HappyCodings"); return 0; }

/* If Else Statement in C++ Language */ #include <iostream> using namespace std; int main () { // local variable declaration: int a = 100; // check the boolean condition if( a < 20 ) { // if condition is true then print the following cout << "a is less than 20;" << endl; } else { // if condition is false then print the following cout << "a is not less than 20;" << endl; } cout << "value of a is : " << a << endl; return 0; }

/* using public and private in C++ Class */ // Program to illustrate the working of // public and private in C++ Class #include <iostream> using namespace std; class Room { private: double length; double breadth; double height; public: // function to initialize private variables void initData(double len, double brth, double hgt) { length = len; breadth = brth; height = hgt; } double calculateArea() { return length * breadth; } double calculateVolume() { return length * breadth * height; } }; int main() { // create object of Room class Room room1; // pass the values of private variables as arguments room1.initData(42.5, 30.8, 19.2); cout << "Area of Room = " << room1.calculateArea() << endl; cout << "Volume of Room = " << room1.calculateVolume() << endl; return 0; }

/* write a C program which demonstrate use of if-else-if ladder statement */ /* Program to Print Day Names using Else If Ladder in C++*/ #include <iostream> using namespace std; int main() { int day; cout << "Enter Day Number: "; cin >> day; cout << "Day is "; if (day == 1) cout << "Sunday" << endl; else if (day == 2) cout << "Monday" << endl; else if (day == 3) cout << "Tuesday" << endl; else if (day == 4) cout << "Wednesday" << endl; else if (day == 5) cout << "Thursday" << endl; else if (day == 6) cout << "Friday" << endl; else cout << "Saturday" << endl; return 0; }

/* namespaces in C++ language */ // A C++ code to demonstrate that we can define // methods outside namespace. #include <iostream> using namespace std; // Creating a namespace namespace ns { void display(); class happy { public: void display(); }; } // Defining methods of namespace void ns::happy::display() { cout << "ns::happy::display()\n"; } void ns::display() { cout << "ns::display()\n"; } // Driver code int main() { ns::happy obj; ns::display(); obj.display(); return 0; }

/* break statement with while loop code example */ // program to find the sum of positive numbers // if the user enters a negative numbers, break ends the loop // the negative number entered is not added to sum #include <iostream> using namespace std; int main() { int number; int sum = 0; while (true) { // take input from the user cout << "Enter a number: "; cin >> number; // break condition if (number < 0) { break; } // add all positive numbers sum += number; } // display the sum cout << "The sum is " << sum << endl; return 0; }

/* While Loop Statement in C++ language */ // program to find the sum of positive numbers // if the user enters a negative number, the loop ends // the negative number entered is not added to the sum #include <iostream> using namespace std; int main() { int number; int sum = 0; // take input from the user cout << "Enter a number: "; cin >> number; while (number >= 0) { // add all positive numbers sum += number; // take input again if the number is positive cout << "Enter a number: "; cin >> number; } // display the sum cout << "\nThe sum is " << sum << endl; return 0; }

/* simple code example by main() function in C++ */ #include <iostream> using namespace std; int main() { int day = 4; switch (day) { case 1: cout << "Monday"; break; case 2: cout << "Tuesday"; break; case 3: cout << "Wednesday"; break; case 4: cout << "Thursday"; break; case 5: cout << "Friday"; break; case 6: cout << "Saturday"; break; case 7: cout << "Sunday"; break; } return 0; }

/* Standard Input Stream (cin) in C++ language */ // cin with Member Functions #include <iostream> using namespace std; int main() { char name[20], address[20]; cout << "Name: "; // use cin with getline() cin.getline(name, 20); cout << "Address: "; cin.getline(address, 20); cout << endl << "You entered " << endl; cout << "Name = " << name << endl; cout << "Address = " << address; return 0; }

/* C++ Algorithm search() function searches the range [first1, last1) for the occurrence of a subsequence defined by the range [first2, last2), and an iterator to the first element is returned. If the subsequence does not exist then an iterator to the last1 is returned. */ /* Search range for subsequence by search() function code example */ #include <iostream> #include <vector> #include <algorithm> using namespace std; int main() { int i, j; // Declaring the sequence to be searched into vector<int> v1 = { 1, 2, 3, 4, 5, 6, 7 }; // Declaring the subsequence to be searched for vector<int> v2 = { 3, 4, 5 }; // Declaring an iterator for storing the returning pointer vector<int>::iterator i1; // Using std::search and storing the result in // iterator i1 i1 = std::search(v1.begin(), v1.end(), v2.begin(), v2.end()); // checking if iterator i1 contains end pointer of v1 or not if (i1 != v1.end()) { cout << "vector2 is present at index " << (i1 - v1.begin()); } else { cout << "vector2 is not present in vector1"; } return 0; }

/* Assignment operators are used to assigning value to a variable. The left side operand of the assignment operator is a variable and right side operand of the assignment operator is a value. The value on the right side must be of the same data-type of the variable on the left side otherwise the compiler will raise an error. */ // C++ program to demonstrate working of Assignment operators #include <iostream> using namespace std; int main() { // Assigning value 10 to a // using "=" operator int a = 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by adding 10 to a // using "+=" operator a += 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by subtracting 10 from a // using "-=" operator a -= 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by multiplying 10 to a // using "*=" operator a *= 10; cout << "Value of a is "<<a<<"\n"; // Assigning value by dividing 10 from a // using "/=" operator a /= 10; cout << "Value of a is "<<a<<"\n"; return 0; }

/* the switch statement helps in testing the equality of a variable against a set of values */ #include <iostream> using namespace std; int main () { // local variable declaration: char grade = 'D'; switch(grade) { case 'A' : cout << "Excellent!" << endl; break; case 'B' : case 'C' : cout << "Well done" << endl; break; case 'D' : cout << "You passed" << endl; break; case 'F' : cout << "Better try again" << endl; break; default : cout << "Invalid grade" << endl; } cout << "Your grade is " << grade << endl; return 0; }

/* A constructor is a special type of member function that is called automatically when an object is created. In C++, a constructor has the same name as that of the class and it does not have a return type. */ #include <iostream> using namespace std; // declare a class class Wall { private: double length; double height; public: // initialize variables with parameterized constructor Wall(double len, double hgt) { length = len; height = hgt; } // copy constructor with a Wall object as parameter // copies data of the obj parameter Wall(Wall &obj) { length = obj.length; height = obj.height; } double calculateArea() { return length * height; } }; int main() { // create an object of Wall class Wall wall1(10.5, 8.6); // copy contents of wall1 to wall2 Wall wall2 = wall1; // print areas of wall1 and wall2 cout << "Area of Wall 1: " << wall1.calculateArea() << endl; cout << "Area of Wall 2: " << wall2.calculateArea(); return 0; }

/* C++ allows us to allocate the memory of a variable or an array in run time. This is known as dynamic memory allocation. The new operator denotes a request for memory allocation on the Free Store. If sufficient memory is available, new operator initializes the memory and returns the address of the newly allocated and initialized memory to the pointer variable. */ /* Allocate storage space by operator new */ // C++ program code example to illustrate dynamic allocation and deallocation of memory using new and delete #include <iostream> using namespace std; int main () { // Pointer initialization to null int* p = NULL; // Request memory for the variable // using new operator p = new(nothrow) int; if (!p) cout << "allocation of memory failed\n"; else { // Store value at allocated address *p = 29; cout << "Value of p: " << *p << endl; } // Request block of memory // using new operator float *r = new float(75.25); cout << "Value of r: " << *r << endl; // Request block of memory of size n int n = 5; int *q = new(nothrow) int[n]; if (!q) cout << "allocation of memory failed\n"; else { for (int i = 0; i < n; i++) q[i] = i+1; cout << "Value store in block of memory: "; for (int i = 0; i < n; i++) cout << q[i] << " "; } // freed the allocated memory delete p; delete r; // freed the block of allocated memory delete[] q; return 0; }