C++ Tutorial Index

C++ Tutorial C++ History C++ Installation C++ First Program C++ cin and cout C++ Data type C++ Variable C++ operator C++ Keywords

C++ Control Statements

C++ If C++ Nested if C++ If-else C++ If-else-if C++ Switch C++ Break C++ Continue C++ Goto C++ For loop C++ While loop C++ Do while loop

C++ Functions

C++ Call by Value C++ Call by Reference C++ Recursion Function C++ Inline function C++ Friend function

C++ Arrays

Single dimension array Two dimension array

C++ Strings

C++ Strings

C++ Inheritance

C++ Inheritance Single level Inheritance Multilevel Inheritance Multiple Inheritance Hierarchical Inheritance Hybrid Inheritance

C++ Polymorphism

C++ Polymorphism C++ Overloading C++ Overriding C++ Virtual Function

C++ Pointers

C++ Pointers C++ this pointer

C++ Exception Handling

C++ Exception Handling

C++ Constructors

C++ Constructors Default Constructor Parameterize Constructor Copy constructor Constructor Overloading Destructor

C++ File Handling

C++ File Handling C++ Writing to file C++ Reading file C++ Close file

Miscellaneous

C Vs C++ C++ Comments C++ Data Abstraction C++ Identifier C++ Memory Management C++ Storage Classes C++ Void Pointer C++ Array To Function C++ Expressions C++ Features C++ Interfaces C++ Encapsulation std::min in C++ External merge sort in C++ Remove duplicates from sorted array in C++ Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ C++ References C++ Friend Functions C++ Mutable keyword Unary Operators in C++ Initialize Array of objects with parameterized constructors in C++ Differences between #define & const in C/C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort Storage Classes in C Vector resize() in C++ Passing by Reference Vs. Passing by the pointer in C++ Free vs delete() in C++ goto statement in C and C++ C++ program to read string using cin.getline() C++ String Concatenation Heap Sort in C++ Swap numbers in C++ Input Iterators in C++ Fibonacci Series in C++ C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque Function Pointer in C++ Sizeof() Operators in C++ C++ array of Pointers free() Vs delete in C Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Math Functions C++ Object Class C++ Queue Initialize Vector in C++ Vector in C++ C++ STL Components Function overloading in C++ C++ Maximum Index Problem C++ find missing in the second array C++ Program to find the product array puzzle C++ Program To Find Largest Subarray With 0 Sum C++ Program To Move All Zeros To The End Of The Array C++ Program to find the element that occurs once C++ Program to find the largest number formed from an array Constructor Vs Destructor C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor C++ vs C# Malloc() and new in C++ Palindrome Number Program in C++ Snake Code in C++ Splitting a string in C++ Structure Vs Class in C++ Virtual Function Vs Pure Virtual Function C++ Bidirectional Iterators C++ Forward Iterators C++ Iterators C++ Output Iterators C++ Range-based For Loop Converting string into integer in C++ LCM Program in C++ Type conversion in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ Armstrong Number Program in C++ ATM machine program in C++ using functions Binary to Decimal in C++ Bit Manipulation in C++ C++ Constructor C++ Dijkstra Algorithm Using the Priority Queue C++ int into String C++ Signal Handling Decimal to Binary in C++ Decimal to Hexadecimal in C++ Decimal to Octal in C++ Factorial Program in C++ Function in C++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ Structure Vs Class in C++ C++ Forward Iterators C++ Output Iterators C++ Prime number program Char Array to String in C++ Constructor Overloading in C++ Default arguments in C++ Different Ways to Compare Strings in C++ Dynamic Binding in C++ Program to convert infix to postfix expression in C++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast Input and Output in C++ Delete Operator in C++ Copy elision in C++ C++ Date and Time C++ Bitwise XOR Operator Array of sets in C++ Binary Operator Overloading in C++ Binary Search in C++ Implementing the sets without C++ STL containers Scope Resolution Operator in C++ Smart pointers in C++ Types of polymorphism in C++ Exception Handling in C++ vs Java Const Keyword in C++ Type Casting in C++ Static keyword in C++ vs Java Inheritance in C++ vs Java How to concatenate two strings in C++ Programs to Print Pyramid Patterns in C++ swap() function in C++ Structure of C++ Program Stringstream in C++ and its applications rand() and srand() in C / C++ C++ Ternary Operator C++ Scope of Variables While Loop Examples in C++ Star pattern in C++ using For Loops For Loop Examples in C++ Do-While Loop Examples in C++ Top 5 IDEs for C++ That You Should Try Once Assertions in C/C++ C++ Convert Int to String Continue in C++ While loop Diamond Pattern in C++ using For Loop How to Reverse a String in C++ using Do-While Loop How to Reverse a String in C++ using For Loop How to Reverse a String in C++ using While Loop Infinite loop in C++ Loops in C++ Returning Multiple Values from a Function using Tuple and Pair in C++ wcscpy(), wcslen(), wcscmp() Functions in C++ Auto keyword in C++ C++ 11 vs C++ 14 vs C++ 17 C++ STL (Standard Template Library) Differences Between C Structures and C++ Structures Divide by Zero Exception in C++ Dynamic Constructor in C++ Dynamic Memory Allocation in C++ Find the Size of Array in C/C++ without using sizeof() function Floating Point Operations and Associativity in C, C++ and Java Hello World Program in C++ How to create a table in C++ How to Setup Environment for C++ Programming on Mac Implementation of a Falling Matrix in C++ Message Passing in C++ Pointer to Object in C++ Templates in C++ vs Generics in Java Ways to Copy a Vector in C++ What does Buffer Flush mean in C++ sort() function in C++ Structure Sorting (By Multiple Rules) in C++ Similarities between C++ and Java std::distance in C++ Array program in C++ C++ Tricks for Competitive Programming Desired Capabilities in Selenium Web Driver in C++ Socket Programming in C++ Template Specialization in C++ Classes and Objects in C++ Convex hull Algorithm in C++ DES in C++ C++ vardiac() function Difference between Two Sets in C++ Difference between Exit and Return Structured Binding in C++ Differences between Local and Global Variable Bitwise Operator vs Logical Operator Difference between OOP and POP in C++ Fork in C++ Functors in C++ How to call a void function in C++ How to create a directory or folder in C/C++ How to create a library in C++ How to create a stack in C++ How to create the Processes with Fork in C++ How to Handle Divide by Zero Exception in C++ Lambda Expression in C++ Pattern programs in C++ Roadmap to C++ Programming Substring in C++ Virtual base class in C++ Bits stdc++.h in C++ Top 14 Best Free C++ IDE (Editor & Compiler) for Windows in 2022 Bitmasking in C++ Auto Keyword in C++ Features of OOPS in C++ Hospital Management Project in C++ How to Declare Unordered Sets in C++ How to Sort an Array in C++ Include Guards in C++ Iostream in C++ Method overriding in C++ How to run program in turbo c++ How to Use Getline in C++ Leap Year Program in C++ Naming Convention in C++ New Operator in C++ Nullptr in C++ Object Slicing in C++ Principles of Object-Oriented Programming in C++ Processing strings using std string stream in C++ Pure Virtual Function in C++ With Example Program Random Number Generator in C++ Singleton Design Pattern in C++ Size_t Data Type in C++ Skyline Problem in C++ System() function in C++ Web Development in C++ Data Hiding in C++ Difference between exit() and _Exit() in C++ Hashing in C++ Object in C++ Sum of all Elements between k1’th and k2’th Smallest Elements Virtual class in C++ Vector Size in C++ Top best IDEs for C/C++ Developers in 2022 Tensorflow in C++ Sliding Window Technique in C++ Reverse String Word-Wise in C++ Returning a Function Pointer from a Function in C/C++ RTTI in C++ Pthreads or POSIX Threads in C++ Reserved Keywords in C++ Passing a Vector to a function in C++ 10 Best C and C++ Books for Beginners & Advanced Programmers Add two numbers represented by two arrays in C++ Array of Object in C++ C++ Program For FCFS Containership in C++ Counting Frequencies of Array Elements in C++ Decltype type Specifier in C++ Dynamic _Cast in C++ Difference between int main() and int main(void) in C/C++ Depth First Search Program to Traverse a Graph in C++ Features and Use Of Pointers in C/C++ Fread Function in C++ Programming Fscanf Function in The C++ Functions in C++ With Types and Examples Gmtime Function in C/C++ How is Multiset Implemented in C++ How to Build a Program in C++ How to Declare a 2d Array Dynamically in C++ inheritance Program in C++ int Max and int Min in C/C++ is It Fine to Write Void Main Or Main in C/C++ How to create a button in C++ abs() function in C++ Compile Time Polymorphism in C++ Division in C++ Factorial of a Number in C++ using while Loop Multiset in C++ 4 Pillars of OOPs Approach in C++ Backtracking Time Complexity in C++ C++ Global Variable C++ Pipe Tutorial Observer Design Pattern in C++ Private Inheritance in C++ Pthread in C++ Parameters SDL library in C++ with Examples Pointers in C++ Abstract Factory Design Pattern in C++ Ascending order in C++ How the value is passed in C++ Call by Pointer in C++ Constexpr in C++ Deadlock in C++ Design Patterns in C++ Factory Method for Designing Pattern in C++ How to calculate size of string in C++ Name Mangling and extern in C++ Preventing Object Copy in C++ Program that produces different results in C and C++ Quick Sort in C++ Single Handling in C++ Type difference of Character literals in C VS C++ Use of Inheritance in C++ User-defined literals in C++ Vector methods in C++ Void * in C and C++ Zombie and Orphan Process in C++ Isprint() in C++ List and Vector in C++ List iterators in C++ Merging Two Vectors in C++ Sleep function in C++ Stoi function in C++ String erase() in C++ String Trim in C++ When should we write own Assignment operator in C++ C++ tcp client server example C++ tcp server example Early Binding and Late Binding in C++ Factory Design Pattern in C++ Fisher-Yates shuffle algorithm in C++ For Auto in C++ Group anagrams in C++ How to convert binary string to int in C++ How to convert string to float in C++ How to remove space from string in C++ How to use pair in C++ How to use the string find() in C++ Dynamic Casting in C++ 2D Vector Initialization in C++ C++ GUI Visual Studio C++ IPC C++ Macro Function Example C++ Permutation Overloading Stream Insertion in C++ Overloading array Index operator in C++ Operators that cannot be overloaded in C++ Operator overloading in C++ isprint() function in c++ Is_trivial function in C++ Is assignment operator Inherited in C++ div() function in C++ Default Assignment Operator and References in C++ Copy Constructor vs Assignment Operator in C++ Conversion Operator in C++ Array sum in C++ STL C++ Define Macro C++ Design C++ Factory Pattern TCP Client Server Example in C++ Convert String to Uppercase in C++ exit() and _Exit() in C and C++ Initializer list in C++ Iterator invalidation in C++ Lower bound in C++ Modulus of Two float numbers or double number Pass by value in C++ Set insert function in C++ Std partition_point in C++ Unary Operator Overloading in C++ Using Default Arguments with Virtual Functions Virtual Functions and Runtime Polymorphism What is endl in C++ What is Unary Operator Overloading in C++ Which operators cannot be overloaded in C++ C++ Program to Divide the String Into N equal Parts Gray Code to Binary Code in C++ How to get the value of pi in C++ Multimap value_comp() function in C++ Vector of Vectors in C++ Naïve Bayes Algorithm in C++ Minimum Cost Path Problem in C++ 10 C++ Programming Tricks You Should Know btowc() function in C++ forward_list::cend() in C++ Unordered_multimap max_load_factor() function in C++ Cpp_int in c++ Dynamic Objects in C++ FLOCK() FUNCTION IN C++ Generate Random Double Numbers in C++ How to Assign Infinity to a Number in C++ Jump statements in C++ Multipath inheritance in C++ Out of Range Exception in C++ Size of Class in C++ Size of string in C++ std::binary_negate in c++ Thread_local in C++ Tokenizing a String in C++ Ancestors of a Node in Binary Search Tree C++ program for Double to String Conversion C++ Program to Demonstrate Use of Formatting Flags on Float Output Clamp in C++ K-Dimensional Tree in C++ Mutable Lambda in C++ Power Set in C++ Program to Find Sum of Geometric Progression Std::Back_inserter in C++ Strpbrk() function in C++ Size of int in C++ TYPES OF MANIPULATORS IN C++ Double colon in C++ How to sort vector in C++ How to use Setprecision in C++ How to write a Vector in C++ Insertion in Splay Tree in C++ Merge Sort Algorithm in C++ Printing a Character using ASCII value in C++ Regex in C++ Size of Data Types in C++ Sqrtf() function in C++ Static Casting in C++ Using Range in Switch Case in C++ wcstoimax() and wcstoumax() function in C++ What is float in C++ What is the Diamond Problem in C++ Best way to learn C++ ios setstate() function in C++ Nested Namespace in C++ Single Inheritance in C++ std::fixed, std::scientific, std::hexfloat, std::defaultfloat in C++ StringStream in C++ for Decimal to Hexadecimal and back The OFFSETOF() macro in C++ Difference between std::next and std::advance in C++ Hiding of all overloaded methods with same name in base class in C++ C++ program to concatenate two strings using operator overloading Difference between array::fill() and array::swap() in C++ Difference between Friend Function and Virtual Function in C++ Semaphores in C++ Seekg in C++ UDP server- client implementattion in C++ What is long long in C++ CSV file management using C++ Toggle bits of a number except first and last bits in C++ Trailing Return Type C++ 11 Binary search implementation in C++ Different Versions of C++ What is Cascading in C++ Background Colour in C++ BOOL DATATYPE IN C++ BIT VECTORS IN C++ Literals in C++ Application of pointer in C++ Index with minimum sum of prefix and suffix sums in an array in C++ Maximum sum Bi-tonic sub-sequence in C++ std::optional in C++ C/C++ program for triangular matchstick number COUT COMMAND IN C++ LANGUAGE Adjacency matrix program in C++ language Difference between Null String and Empty String in C++ Character data type in c++ Constructors in Inheritance C++ Comma Operator Overloading in C++ Structure and Class in C++ Template Definition in C++ Tree Data Structure in C++ Typename in C++ C++ program to implement the bin packing algorithm How to merge multiple std::sets into a single std::set in C++? Stack Clear C++ C++ Friend Class Seekg in C++ Semaphores in C++ C++ Exceptions Difference Between C and C++ Double-linked list program in C++ Color Code in C++ CRC Program in C++ Anti-Clockwise spiral traversal of a binary tree in C++ Advantages of OOP in C++ Cryptarithmetic Puzzle in C++ Angular sweep algorithm in C++ How to Access Private Variables in C++? Particle Swarm Optimization in C++ Understanding std::ios_base::iword in C++ std::piecewise_construct _t in C++ Toeplitz Matrix in C++ Two-Way Linear Search Algorithm in C++ C++ Concurrency in action C++ integer size C++ Enum class Compare two lists in C++ Command to run C++ Program in terminal Cascading In C++ Static Member Function in C++ with Example C++ Multiple, Multilevel and Hierarchical inheritance Painting Fence Algorithm in C++ Rearrange Distant Barcodes in C++ What are the rules for using an Underscore in a C++ dentifier? std::quoted in C++ Std::memory_order in C++ Std::fisher_f_distribution in C++ Advantages Oops in C++ floor() and ceil() function in C++ Topological Sort in C++ How to get file size in C++ Class Meaning in C++ DIFFERENCE BETWEEN NEW AND DELETE OPERATOR IN C++ New and Delete In C++ Operators in C++ String data types in C++ begin() in C++

Using Default Arguments with Virtual Functions

Introduction

C++ is a versatile language that supports several features, including virtual functions and default arguments. Together, these two capabilities can increase the flexibility and maintainability of your code.In this article, we will discuss how to use default arguments with virtual functions in C++.

  • Default Arguments

In C++, you can define default arguments for function parameters.You can define a default argument by simply giving the parameter in the function declaration a value. To define a default argument, you simply assign a value to the parameter in the function declaration. For example:

void foo(int x = 0) {
    // function body


}

In the above example, the default value of the parameter x is 0. The function will utilise the value it receives as input in place of the default value. In the absence of a value, the default value of 0 will be applied.

Virtual Functions

A virtual function is a class member function that a derived class may override. When objects of various classes are polymorphic, they can be utilised interchangeably if they share a virtual function. To declare a virtual function in C++, you use the virtual keyword in the function declaration. For example:

class Shape {
public:
    virtual double area() { return 0; }
};

In the above example, the area() function is declared as a virtual function. This means that it can be overridden by a derived class. The implementation in the base class returns 0 as a default value.

Using Default Arguments with Virtual Functions

When you use default arguments with virtual functions, the default argument is used by the derived class if the derived class does not provide its own implementation of the function. Consider the following example:

#include <iostream>
using namespace std;


class Shape {
public:
    virtual double area(double r = 0) { return 0; }
};


class Circle : public Shape {
public:
    double area(double r = 0) override {
        return 3.141592 * r * r;
    }
};


int main() {
    Circle circle;
    Shape* shape = &circle;


    cout << "Area of circle: " << shape->area() << endl; // prints "Area of circle: 0"
    cout << "Area of circle with radius 2: " << shape->area(2) << endl; // prints "Area of circle with radius 2: 12.5664"


    return 0;
}

Explanation

  • This program demonstrates the use of default arguments and virtual functions in C++.
  • The program defines a base class Shape which has a virtual function named area(). This function takes a parameter r which has a default value of 0. The implementation of this function in the Shape class simply returns 0.
  • The Circle class is a derived class of Shape and overrides the area() function. In this implementation, the area() function takes a default parameter r of 0 and calculates the area of the circle using the formula pr^2.
  • In the main() function, an object of the Circle class is created, and a pointer of type Shape is assigned to it. The area() function is called on this pointer using shape->area(), which prints 0 since the function is called with the default argument value of 0.
  • Next, the area() function is used to compute the area of the circle with a radius of 2 and print the result. This method is called with a value of 2 for the r parameter.

Program Output:

Using Default Arguments with Virtual Functions

Here is another example program that demonstrates the use of default arguments and virtual functions in C++:

Program

#include<iostream>
using namespace std;


// define a function with default arguments
void myFunction(int x, int y = 0, int z = 1) {
std::cout << "x = " << x << ", y = " << y << ", z = " << z << std::endl;
}


// define a base class with a virtual function
class Shape {
public:
    virtual void draw() {
std::cout << "You can Draw a shape." <<std::endl;
    }
};


// define a derived class that overrides the virtual function
class Circle : public Shape {
public:
    void draw() override {
std::cout <<"You can Draw a circle." << std::endl;
    }
};


int main() {
    // call myFunction with default arguments
myFunction(5);          // output: x = 5, y = 0, z = 1
myFunction(5, 10);      // output: x = 5, y = 10, z = 1
myFunction(5, 10, 15);  // output: x = 5, y = 10, z = 15


    // create instances of Shape and Circle
    Shape* shape = new Shape();
    Circle* circle = new Circle();


    // call the draw() function on the instances
    shape->draw();   // output: Drawing a shape.
    circle->draw();  // output: Drawing a circle.


    // delete the instances
    delete shape;
    delete circle;


    return 0;
}

Explanation:

  • The program starts by defining a function myFunction() that takes three integer parameters, with default values of 0 and 1 for the second and third parameters, respectively. If the function is called with only one argument, the other two arguments will be set to their default values.
  • The programme then creates a basic class called Shape and adds a virtual function called draw (). A function that is declared in a base class and can be overridden by a derived class is referred to as a virtual function. In this instance, the draw() function is virtual, which means that any derived class may override it.
  • The draw() function is then overridden in a derived class called Circle by the programme.Theoverride keyword is used to indicate that the function is intended to override a virtual function from the base class.
  • In the main() function, the program calls the myFunction() function with different numbers of arguments, demonstrating how default arguments can make a function more flexible.
  • The program then creates instances of the Shape and Circle classes using pointers, and calls the draw() function on each instance. The draw() function of the Circle class overrides the draw() function of the Shape class so that the output will be different for each instance.
  • Finally, the program deletes the instances to avoid memory leaks.

Program Output:

Using Default Arguments with Virtual Functions

Benefits of using Default Arguments with Virtual Functions

Flexibility: Default arguments can provide flexibility in the implementation of virtual functions. By providing default values for function arguments, developers can create functions that are more versatile and can be called in different ways depending on the specific requirements of the program.

Simplicity: Default arguments make it easier to use virtual functions in a way that makes sense for the specific use case.The code could be made more manageable and straightforward as a result.

Efficiency: Using default arguments in virtual functions can sometimes improve the performance of the program by allowing the compiler to optimize the code more effectively.

Drawback of using Default Arguments with Virtual Functions

Ambiguity: Using default arguments with virtual functions can sometimes create ambiguity in the code. When there are multiple functions with the same name, the compiler may be unable to determine which function to call if the arguments are not specified explicitly. This may cause the software to behave unexpectedly and include errors.

Complexity: While default arguments can simplify the code, they can also make it more complex and difficult to understand. This is especially true when the default arguments are not well documented or when they are changed over time.

Compatibility: Not all programming languages support default arguments with virtual functions. It may become more challenging to maintain and upgrade the code over time and its portability may be restricted as a result.

Conclusion

In conclusion, default arguments and virtual functions are two important features of C++ that can make code more flexible, efficient, and maintainable.

Default arguments allow you to specify default values for function parameters so they can be omitted when calling the function. This can help your code be clearer and simpler to comprehend, especially when working with functions that have a lot of parameters.

On the other hand, virtual functions let you specify a function in a base class that can be overridden by a derived class. This allows you to write more generic code that can be customized by different classes, which can make your code more reusable and easier to maintain.

When used together, default arguments and virtual functions can make your code even more powerful and flexible. For example, you can define a virtual function with default arguments in a base class, and then override it with different default arguments in a derived class. This can give you even more control over how your code behaves while allowing you to reuse common functionality.