# C++ Programming Code Examples

## C++ > Computer Graphics Code Examples

### Program to Perform Left Rotation on a Binary Search Tree

/* Program to Perform Left Rotation on a Binary Search Tree This is a C++ Program to perform Left Rotation in Binary Search Trees. In discrete mathematics, tree rotation is an operation on a binary tree that changes the structure without interfering with the order of the elements. A tree rotation moves one node up in the tree and one node down. It is used to change the shape of the tree, and in particular to decrease its height by moving smaller subtrees down and larger subtrees up, resulting in improved performance of many tree operations. There exists an inconsistency in different descriptions as to the definition of the direction of rotations. Some say that the direction of a rotation depends on the side which the tree nodes are shifted upon whilst others say that it depends on which child takes the root's place (opposite of the former). This article takes the approach of the side where the nodes get shifted to. */ #include<iostream> #include<cstdio> #include<sstream> #include<algorithm> #define pow2(n) (1 << (n)) using namespace std; /* Node Declaration */ struct avl_node { int data; struct avl_node *left; struct avl_node *right; }*root; /* Class Declaration */ class avlTree { public: int height(avl_node *); int diff(avl_node *); avl_node *rr_rotation(avl_node *); avl_node *ll_rotation(avl_node *); avl_node *lr_rotation(avl_node *); avl_node *rl_rotation(avl_node *); avl_node* balance(avl_node *); avl_node* insert(avl_node *, int); void display(avl_node *, int); void inorder(avl_node *); void preorder(avl_node *); void postorder(avl_node *); avlTree() { root = NULL; } }; /* Main Contains Menu */ int main() { int choice, item; avlTree avl; while (1) { cout << "\n---------------------" << endl; cout << "AVL Tree Implementation" << endl; cout << "\n---------------------" << endl; cout << "1.Insert Element into the tree" << endl; cout << "2.Display Balanced AVL Tree" << endl; cout << "3.InOrder traversal" << endl; cout << "4.PreOrder traversal" << endl; cout << "5.PostOrder traversal" << endl; cout << "6.Exit" << endl; cout << "Enter your Choice: "; cin >> choice; switch (choice) { case 1: cout << "Enter value to be inserted: "; cin >> item; root = avl.insert(root, item); break; case 2: if (root == NULL) { cout << "Tree is Empty" << endl; continue; } cout << "Balanced AVL Tree:" << endl; avl.display(root, 1); break; case 3: cout << "Inorder Traversal:" << endl; avl.inorder(root); cout << endl; break; case 4: cout << "Preorder Traversal:" << endl; avl.preorder(root); cout << endl; break; case 5: cout << "Postorder Traversal:" << endl; avl.postorder(root); cout << endl; break; case 6: exit(1); break; default: cout << "Wrong Choice" << endl; } } return 0; } /* Height of AVL Tree */ int avlTree::height(avl_node *temp) { int h = 0; if (temp != NULL) { int l_height = height(temp->left); int r_height = height(temp->right); int max_height = max(l_height, r_height); h = max_height + 1; } return h; } /* Height Difference */ int avlTree::diff(avl_node *temp) { int l_height = height(temp->left); int r_height = height(temp->right); int b_factor = l_height - r_height; return b_factor; } /* Right- Right Rotation */ avl_node *avlTree::rr_rotation(avl_node *parent) { avl_node *temp; temp = parent->right; parent->right = temp->left; temp->left = parent; return temp; } /* Left- Left Rotation */ avl_node *avlTree::ll_rotation(avl_node *parent) { avl_node *temp; temp = parent->left; parent->left = temp->right; temp->right = parent; return temp; } /* Left - Right Rotation */ avl_node *avlTree::lr_rotation(avl_node *parent) { avl_node *temp; temp = parent->left; parent->left = rr_rotation(temp); return ll_rotation(parent); } /* Right- Left Rotation */ avl_node *avlTree::rl_rotation(avl_node *parent) { avl_node *temp; temp = parent->right; parent->right = ll_rotation(temp); return rr_rotation(parent); } /* Balancing AVL Tree */ avl_node *avlTree::balance(avl_node *temp) { int bal_factor = diff(temp); if (bal_factor > 1) { if (diff(temp->left) > 0) temp = ll_rotation(temp); else temp = lr_rotation(temp); } else if (bal_factor < -1) { if (diff(temp->right) > 0) temp = rl_rotation(temp); else temp = rr_rotation(temp); } return temp; } /* Insert Element into the tree */ avl_node *avlTree::insert(avl_node *root, int value) { if (root == NULL) { root = new avl_node; root->data = value; root->left = NULL; root->right = NULL; return root; } else if (value < root->data) { root->left = insert(root->left, value); root = balance(root); } else if (value >= root->data) { root->right = insert(root->right, value); root = balance(root); } return root; } /* Display AVL Tree */ void avlTree::display(avl_node *ptr, int level) { int i; if (ptr != NULL) { display(ptr->right, level + 1); printf("\n"); if (ptr == root) cout << "Root -> "; for (i = 0; i < level && ptr != root; i++) cout << " "; cout << ptr->data; display(ptr->left, level + 1); } } /* Inorder Traversal of AVL Tree */ void avlTree::inorder(avl_node *tree) { if (tree == NULL) return; inorder(tree->left); cout << tree->data << " "; inorder(tree->right); } /* Preorder Traversal of AVL Tree */ void avlTree::preorder(avl_node *tree) { if (tree == NULL) return; cout << tree->data << " "; preorder(tree->left); preorder(tree->right); } /* Postorder Traversal of AVL Tree */ void avlTree::postorder(avl_node *tree) { if (tree == NULL) return; postorder(tree ->left); postorder(tree ->right); cout << tree->data << " "; }

A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.

Switch statement in C tests the value of a variable and compares it with multiple cases. Once the case match is found, a block of statements associated with that particular case is executed. Each case in a block of a switch has a different name/number which is referred to as an identifier. The value provided by the user is compared with all the cases inside the switch block until the match is found. If a case match is NOT found, then the default statement is executed, and the control goes out of the switch block. • The expression can be integer expression or a character expression. • Value-1, 2, n are case labels which are used to identify each case individually. Remember that case labels should not be same as it may create a problem while executing a program. Suppose we have two cases with the same label as '1'. Then while executing the program, the case that appears first will be executed even though you want the program to execute a second case. This creates problems in the program and

In C++, constructor is a special method which is invoked automatically at the time of object creation. It is used to initialize the data members of new object generally. The constructor in C++ has the same name as class or structure. Constructors are special class functions which performs initialization of every object. The Compiler calls the Constructor whenever an object is created. Constructors initialize values to object members after storage is allocated to the object. Whereas, Destructor on the other hand is used to destroy the class object. • Default Constructor: A constructor which has no argument is known as default constructor. It is invoked at the time of creating object.

#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.

Allocate storage space. Default allocation functions (single-object form). A new operator is used to create the object while a delete operator is used to delete the object. When the object is created by using the new operator, then the object will exist until we explicitly use the delete operator to delete the object. Therefore, we can say that the lifetime of the object is not related to the block structure of the program.

Continue statement is used inside loops. Whenever a continue statement is encountered inside a loop, control directly jumps to the beginning of the loop for next iteration, skipping the execution of statements inside loop's body for the current iteration. The continue statement works somewhat like the break statement. Instead of forcing termination, however, continue forces the next iteration of the loop to take place, skipping any code in between. For the for loop, continue causes the conditional test and increment portions of the loop to execute. For the while and do...while loops, program control passes to the conditional tests.

Consider a situation, when we have two persons with the same name, jhon, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother's or father's name, etc. Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function you are referring to within your code.

In the C++ Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. Macro definitions are not variables and cannot be changed by your program code like variables. You generally use this syntax when creating constants that represent numbers, strings or expressions. The syntax for creating a constant using #define in the C++ is: #define token value

The exit function terminates the program normally. Automatic objects are not destroyed, but static objects are. Then, all functions registered with atexit are called in the opposite order of registration. The code is returned to the operating system. An exit code of 0 or EXIT_SUCCESS means successful completion. If code is EXIT_FAILURE, an indication of program failure is returned to the operating system. Other values of code are implementation-defined. Calls all functions registered with the atexit() function, and destroys C++ objects with static storage duration, all in last-in-first-out (LIFO) order. C++ objects with static storage duration are destroyed in the reverse order of the completion of their constructor. (Automatic objects are not destroyed as a result of calling exit().)

Break statement in C++ is a loop control statement defined using the break keyword. It is used to stop the current execution and proceed with the next one. When a compiler calls the break statement, it immediately stops the execution of the loop and transfers the control outside the loop and executes the other statements. In the case of a nested loop, break the statement stops the execution of the inner loop and proceeds with the outer loop. The statement itself says it breaks the loop. When the break statement is called in the program, it immediately terminates the loop and transfers the flow control to the statement mentioned outside the loop.

The if...else statement executes two different codes depending upon whether the test expression is true or false. Sometimes, a choice has to be made from more than 2 possibilities. The if...else ladder allows you to check between multiple test expressions and execute different statements. In C/C++ if-else-if ladder helps user decide from among multiple options. The C/C++ if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the C else-if ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.

Logical Operators are used to compare and connect two or more expressions or variables, such that the value of the expression is completely dependent on the original expression or value or variable. We use logical operators to check whether an expression is true or false. If the expression is true, it returns 1 whereas if the expression is false, it returns 0. Assume variable A holds 1 and variable B holds 0:

The cin object is used to accept input from the standard input device i.e. keyboard. It is defined in the iostream header file. C++ cin statement is the instance of the class istream and is used to read input from the standard input device which is usually a keyboard. The extraction operator(>>) is used along with the object cin for reading inputs. The extraction operator extracts the data from the object cin which is entered using the keyboard. The "c" in cin refers to "character" and "in" means "input". Hence cin means "character input". The cin object is used along with the extraction operator >> in order to receive a stream of characters.

In while loop, condition is evaluated first and if it returns true then the statements inside while loop execute, this happens repeatedly until the condition returns false. When condition returns false, the control comes out of loop and jumps to the next statement in the program after while loop. The important point to note when using while loop is that we need to use increment or decrement statement inside while loop so that the loop variable gets changed on each iteration, and at some point condition returns false. This way we can end the execution of while loop otherwise the loop would execute indefinitely. A while loop that never stops is said to be the infinite while loop, when we give the condition in such a way so that it never returns false, then the loops becomes infinite and repeats itself indefinitely.

In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement, The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.

In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.

The main purpose of C++ programming is to add object orientation to the C programming language and classes are the central feature of C++ that supports object-oriented programming and are often called user-defined types. A class is used to specify the form of an object and it combines data representation and methods for manipulating that data into one neat package. The data and functions within a class are called members of the class.

In C++, classes and structs are blueprints that are used to create the instance of a class. Structs are used for lightweight objects such as Rectangle, color, Point, etc. Unlike class, structs in C++ are value type than reference type. It is useful if you have data that is not intended to be modified after creation of struct. C++ Structure is a collection of different data types. It is similar to the class that holds different types of data. A structure is declared by preceding the struct keyword followed by the identifier(structure name). Inside the curly braces, we can declare the member variables of different types.

Insertion sort is simple sorting algorithm that builds the final sorted array ('or list') one item at a time. It is much less efficient on large lists than more advanced algorithms such as quick

Generates a undirected random graph for the given number "edges and vertexes". The time complexity of this algorithm is O(v*e). Takes the input of the number of vertexes & edges

If a number passed to checkPrimeNumber() is a Prime Number, this function returns true, if not the Function returns false. If enters larger number first, 'code' will not work as intended.

Algorithm finds the "Chromatic Index" of the given cyclic graph. It takes the input of vertex pairs for the given number of edges. Assigns a 'color to edges' without assigning the same