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++ OOPS Concepts 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

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

function in C++ C++ Call by Value C++ Call by Reference C++ Recursion function C++ inline function C++ Friend function C++ Friend functions function Pointer in C++ Sizeof() Operators in C++ C++ Math functions swap() function in C++ rand() and srand() in C / C++ wcscpy(), wcslen(), wcscmp() functions in C++ sort() function in C++ C++ vardiac() function System() function in C++ Fread function in C++ Programming Fscanf function in The C++ Gmtime function in C/C++ abs() function in C++ Sleep function in C++ Stoi function in C++ String erase() in C++ String Trim in C++ isprint() function in c++ is_trivial function in C++ div() function in C++ Set insert function in C++ rint(), rintf(), rintl() in C++ String append() function in C++ String push_back() in C++ String replace() in C++ Transform function in C++ exit() and _Exit() in C and C++ Std partition_point in C++ unique() in C++ ctime() function in C++ Gets() and Puts() in C++ Hypot(), hypotf() and hypotl() in C++ Log function in C++ Nearbyint() function in C++ setf() function in C++ Fill Function in C++ Map Find Function in C++ Malloc and Calloc in C++ Operator Function in C++ cin.get() in C++ seekp() Function in C++ eof() Function in C++ Emplace Back in C++ C++ macro function C_str in C++ Clock() in C/C++ round() function in C++ scalbn() function in C++ Stable Sort function in C++ Rotate in C++ Std:: Sort_heap in C++ Std::includes() in C++ STL std::memset() function in C++ Wcscmp() function in C++ Static Member function in C++ atof() function in C++ C++ Sin() function with Example cin.ignore() function in C++ Member function in C++ Pop_front Vector in C++ Vector resize() in C++ Malloc() and new in C++ std::distance in C++ C++ Date and Time fork() in C++ std::min in C++ isprint() in C++ rdbuf() in C++ fixed() Function in C++ setw() in C++ seekg() Function in C++ isdigit() Function in C++

C++ Function Miscellaneous

Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ function overloading in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ ATM machine program in C++ using functions Returning Multiple Values from a function using Tuple and Pair in C++ Find the Size of Array in C/C++ without using sizeof() function Pure Virtual function in C++ With Example Program Returning a function Pointer from a function in C/C++ Passing a Vector to a function in C++ functions in C++ With Types and Examples C++ Macro function Example Using Default Arguments with Virtual functions Virtual functions and Runtime Polymorphism Fesetround() and Fegetround() in C++ and their application Object as function Argument in C++ Private Member function in C++ Function Overriding in C++ C++ Program for Addition of Two Numbers Using functions function Object in C++ Elements of User Defined function in C++ Inline Functions in C++ Virtual Function in C++

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

C++ Programs

Structure of C++ Program Hello World Program in C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort C++ program to read string using cin.getline() C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle 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 Palindrome Number Program in C++ LCM Program in C++ Armstrong Number Program in C++ Factorial Program in C++ C++ Prime number program Program to convert infix to postfix expression in C++ Programs to Print Pyramid Patterns in C++ Array program in C++ Pattern programs in C++ Leap Year Program in C++ C++ Program for FCFS Depth First Search Program to Traverse a Graph in C++ inheritance Program in C++ Program that produces different results in C and C++ Example Program in C++ for input and Output Calculator Program using Switch in C++ Program for COPY Constructor in C++ Bank Program in C++ Anagram Program in C++

C++ Operators

Unary Operators in C++ Delete Operator in C++ C++ Bitwise XOR Operator Binary Operator Overloading in C++ Scope Resolution Operator in C++ C++ Ternary Operator New Operator in C++ Overloading array index operator in C++ Operator overloading in C++ Operators that cannot be overloaded in C++ Default Assignment Operator and References in C++ Conversion Operator in C++ Unary Operator Overloading in C++ Benefits of Operator Overloading in C++ Assignment Operator Overloading in C++ New and Delete Operator in C++ Insertion Operator in C++ Increment Operator in C++ Bitwise Operator in C++

C++ Examples

C++ Programming Examples While Loop Examples in C++ for Loop Examples in C++ Do-While Loop Examples in C++ SDL library in C++ with Examples C++ tcp client server example C++ tcp server example TCP Client Server Example in C++ Example of Parameterized Constructor in C++ Example of User Defined Data Type in C++

C++ Differences

C Vs C++ free() vs delete() in C++ Constructor Vs Destructor Passing by Reference Vs. Passing by the pointer in C++ C++ vs C# Structure Vs Class in C++ Virtual function Vs Pure Virtual function Structure Vs Class in C++ Exception Handling in C++ vs Java Static keyword in C++ vs Java inheritance in C++ vs Java C++ 11 vs C++ 14 vs C++ 17 Templates in C++ vs Generics in Java Bitwise Operator vs Logical Operator Type difference of Character literals in C VS C++ Copy Constructor vs Assignment Operator in C++ Map vs unordered_map in C++ Differences between #define & const in C/C++ Differences Between C Structures and C++ Structures Difference between Two Sets in C++ Difference between Exit and Return Differences between Local and Global Variable Difference between OOP and POP in C++ Difference between exit() and _Exit() in C++ Difference between int main() and int main(void) in C/C++ Difference Between Overloading and Overriding in C++ std::set_symmetric_difference in C++ Difference between Private and Protected in C++ Difference Between Encapsulation and Abstraction in C++ Difference between Template and Macro in C++ Difference between Abstraction and Interface in C++ Differences Between C++ and Javascript

How To

How to concatenate two strings in C++ 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 How to create a table in C++ How to Setup Environment for C++ Programming on Mac 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++ How to Declare Unordered Sets in C++ How to Sort an Array in C++ How to run program in turbo c++ How to Use Getline in C++ How is Multiset Implemented in C++ How to Build a Program in C++ How to Declare a 2d Array Dynamically in C++ How to create a button in C++ How the value is passed in C++ How to calculate size of string 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++ How to Remove an Element From an Array in C++ How to Take Space Separated input in C++ How to Copy in Turbo C++ How to Use Pow in C++ How to Use Set in C++ How to Create Singleton Class in C++ How to Allocate Memory Dynamically in C++ How to Close Turbo C++ in Windows 10 How to Use Modulus in C++

C++ Questions

What does Buffer Flush mean in C++ What is endl in C++ What is Unary Operator Overloading in C++ Which operators cannot be overloaded in C++ What is Static Member function in C++ What is This Pointer in C++ What is Upcasting in C++ What Kind of Exceptions Are Available in C++ What is Memory Allocation for Objects in C++ What is a Linked List in C++ is assignment operator inherited in C++ When should we write own Assignment operator in C++ What is an Object in C++ What is Copy Constructor in C++ What is a Static Member Function in C++

C++ Interview Questions

Advanced C++ interview Questions Oops Interview Questions in C++


External merge sort in C++ Remove duplicates from sorted array in C++ C++ References C++ Mutable keyword initialize Array of objects with parameterized constructors in C++ Storage Classes in C goto statement in C and C++ C++ String Concatenation Heap Sort in C++ Swap numbers in C++ input Iterators in C++ Fibonacci Series in C++ Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque C++ array of Pointers Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Object Class C++ Queue initialize Vector in C++ Vector in C++ C++ STL Components C++ Maximum index Problem C++ find missing in the second array C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor Snake Code in C++ Splitting a string in C++ C++ Bidirectional Iterators C++ forward Iterators C++ Iterators C++ Output Iterators C++ Range-based for Loop Converting string into integer in C++ Type conversion in C++ 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++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ C++ forward Iterators C++ Output Iterators 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++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast input and Output in C++ Copy elision in C++ Array of sets in C++ Binary Search in C++ Implementing the sets without C++ STL containers Smart pointers in C++ Types of polymorphism in C++ Const Keyword in C++ Type Casting in C++ Stringstream in C++ and its applications C++ Scope of Variables Star pattern in C++ using for Loops 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 infinite loop in C++ Loops in C++ Auto keyword in C++ C++ STL (Standard Template Library) Divide by Zero Exception in C++ Dynamic Constructor in C++ Dynamic Memory Allocation in C++ Floating Point Operations and Associativity in C, C++ and Java Implementation of a Falling Matrix in C++ Message Passing in C++ Pointer to Object in C++ Ways to Copy a Vector in C++ Structure Sorting (By Multiple Rules) in C++ Similarities between C++ and Java 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++ Structured Binding in C++ Functors in C++ Lambda Expression 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++ Features of OOPS in C++ Hospital Management Project in C++ include Guards in C++ Iostream in C++ Method overriding in C++ Naming Convention in C++ Nullptr in C++ Object Slicing in C++ Principles of Object-Oriented Programming in C++ Processing strings using std string stream in C++ Random Number Generator in C++ Singleton Design Pattern in C++ Size_t Data Type in C++ Skyline Problem in C++ Web Development in C++ Data Hiding 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++ RTTI in C++ Pthreads or POSIX Threads in C++ Reserved Keywords 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++ Containership in C++ Counting Frequencies of Array Elements in C++ Decltype type Specifier in C++ Dynamic _Cast in C++ Features and Use of Pointers in C/C++ int Max and int Min in C/C++ is It Fine to Write Void Main Or Main in C/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 Pointers in C++ Abstract Factory Design Pattern in C++ Ascending order in C++ Call by Pointer in C++ Constexpr in C++ Deadlock in C++ Design Patterns in C++ Factory Method for Designing Pattern in C++ Name Mangling and extern in C++ Preventing Object Copy in C++ Quick Sort in C++ Single Handling in 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++ List and Vector in C++ List iterators in C++ Merging Two Vectors in C++ 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++ Dynamic Casting in C++ 2D Vector initialization in C++ C++ GUI Visual Studio C++ IPC C++ Permutation Overloading Stream insertion in C++ Array sum in C++ STL C++ Define Macro C++ Design C++ Factory Pattern Convert String to Uppercase in 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++ Stack size in C++ Unordered_map in C++ Binary String to int C++ Boost C++ Exception handling in constructor and destructor in C++ Explain class template in C++ Kadane Algorithm in C++ Map of Pairs in STL Pair in C++ Access Specifiers in C++ Add Two Numbers in C++ Using Class C++ Socket Programming Windows Cube root in C++ C++ Protected inheritance C++ Return Object Static Data Members in C++ Association in C++ Boost libraries in C++ Automatic Storage Class in C++ C++ Move Constructor Cast in C++ C++ 11 Lambda C++ Multithreading Bottom-up Approach in C++ C++ Static Class C++ Static Member C++ Static Variable C++ Template Class Implementation Kruskals Algorithm in C++ Kth Permutation Sequence in C++ Kth Smallest Element Using Priority Queue in C++ Min Heap in C++ Multilevel inheritance in C++ Playfair Cipher Algorithm in C++ Exception Handling in Java and C++ Sorting in C++ Time and Space Complexity for Loops in C++ Convert Vector To String in C++ Cascading in C++ Control Structure in C++ Passing Object as argument in C++ Vector Pair in C++ String Data Types in C++ Topological Sort in C++ C++ Move Semantics C++ Static Library Linking Call by Value and Call by Reference in C++ Data Structures algorithms and application in C++ Dereferencing a Pointer in C++ Linked List in C++ All Swing Components in C++ anonymous Object in C++ Cerr in C++ Control Flow Statement in C++ cstdlib in C++ Exception Objects in C++ Base Class and Derived Class in C++ Creating A Menu in C++ Escape Sequence in C++ Explicit in C++ int range in C++ Maximum Value in Vector in C++ NPTEL Programming in C++ Shared Pointer in C++ Static Member Function in C++ With Example The Diamond Pattern in C++ Const ptr C++ Const_Cast C++ Area Of Triangle in C++ Array input in C++ Cin String in C++ Coroutine in C++ Gui Design in C++ integer in C++ Advantages and Disadvantages of inheritance in C++ C++ IDE Linux C++ Mini Project With Source Code And Output C++ Variables Types Containers in C++ Dynamic Binding in C++ Explain Access Specifiers in C++ Iomanip in C++ Noexcept in C++ C++ Reference Initializer in C++ Constant Arguments in C++ Vector in C++ Stl Singleton Pattern in C++ Error Handling in C++ C++ Thread Id to Int C Str in C++ C++ Shared Ptr Scope Resolution Operator in C++ C++ Random Number Between 1 and 10 File Opening Mode in C++ New and Delete in C++ Big Integers in C++ Stack Unwinding in C++ C++ Syntax Link Map cbegin() and cend() function in C++ STL Hamming Code Implementation in C++ Files and Streams in C++ Private Destructor 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in C++ Insert Function in C++ Metaclass in C++ Move Constructor in C++ Move Semantics in C++

User-defined literals in C++

Introduction to User-Defined Literals:

User-defined literals, introduced in C++11, are a way to extend the C++ language to allow users to define their literal suffixes and the corresponding behavior. These suffixes can be used to create instances of user-defined types, such as custom classes or enumerations. They can also create instances of built-in types with specific values or formats.

User-defined literals are defined using special suffixes added to the end of a literal value. For example, a developer might define a UDL to represent a length in meters by using the suffix "m" at the end of a numeric value. This would allow them to write code like "5m" instead of "5 * meters" to represent a length of 5 meters.

To define a UDL, a developer must use a special operator called a literal operator, a function that takes a single argument and returns a value of a specific type. The literal operator's name is formed by prefixing the suffix with the keyword operator. So, for example, in the first example, the operator would be called operator""m.

User-defined literals with Built-in Type:

A user-defined literal with a built-in type is a way to define a new literal for a built-in data type, such as int or double, in C++.

This is done by overloading the operator "" (double quotes) and specifying the type of the literal in the function name.

For example, to define a new literal for int, the operator "" _int() could be defined. This would allow the user to create an int variable using the new literal, such as int x = 12_int;

Consider the following code:


long double operator"" _degrees(long double v) {
    return v * 3.14159265358979323846 / 180.0;

int main() {
    double x = 90.0_degrees;
    std::cout << x << std::endl;
    return 0;


  • This code defines a user-defined literal operator, which is a special type of function that can be used to create custom syntax for a program.
  • The operator is defined using the "operator"" _degrees" syntax, where "operator"" _degrees" is the name of the operator, and "long double" is the return type. The operator takes a single argument, "v", which is the value in degrees that the operator will convert to radians.
  • The operator itself performs the conversion by multiplying the value "v" by the constant value of pi divided by 180. This is the conversion factor between degrees and radians.
  • In the main function, the code declares a variable "x" and assigns it the value of 90 degrees in radians by using the "_degrees" suffix after the value 90.0. The "_degrees" is the suffix which we defined in our user-defined operator.
  • Finally, the program uses the "std::cout" function to print the value of x to the console. This will output the value of pi/2 (90 degrees in radians).

Program Output:

User-defined literals

User-defined literals with custom class:

A user-defined literal allows you to define a new literal operator for use with a custom class. This allows us to create objects of our custom class using a syntax that is similar to the syntax used for built-in types.

To define a user-defined literal for a custom class, you need to define a function that takes a string or a character array as its parameter and returns an object of the custom class. This function should be preceded by the keyword "operator" and the literal operator you want to define.

For example, consider the following code:

class MyType {
    int value;
    MyType(int v) : value(v) {}

MyType operator"" _mytype(unsigned long long v) {
    return MyType(v);

int main() {
    MyType x = 10_mytype;
    std::cout << x.value << std::endl;
    return 0;


  • The program defines a simple class called MyType, which has a single public member variable called "value" of type int. The class also has a constructor that takes an int argument and initializes the value variable with that argument.
  • The program also defines a user-defined literal operator overload using the "operator"" _" syntax. This operator overload is a function called "operator"" _mytype", which takes an unsigned long long argument and returns an object of type MyType.
  • The operator overload creates a new MyType object and initializes its value variable with the argument passed to the operator.
  • In the main function, we can see an example of using the user-defined literal. A variable x of type MyType is created and assigned the value 10, followed by the suffix _mytype. This is interpreted by the compiler as a call to the operator overload function, passing the value 10 as the argument.
  • The operator overload function creates a new MyType object and initializes its value variable with 10, and this object is then assigned to the variable x.
  • Finally, the program uses the standard cout to print the value of x, which is 10, the value passed to the operator overload.

Program Output:

User-defined literals

User-defined literals with String Literal:

User-defined literals provide a powerful way to extend the functionality of the C++ language and make it more expressive and user-friendly.

They can be used to create custom classes, enumerations, and built-in types with specific values or formats.

They can also be used to create custom units of measurement, custom date-time formats, custom formatting of numbers, and custom enumerations.

They provide a more natural and intuitive way of expressing values or formats in the code and make the code more expressive, readable, and less error-prone.

Additionally, User-defined literals are widely used in libraries and frameworks to provide a more convenient and expressive API for developers. They also have the ability to create literal operators for string literals, allowing developers to create more expressive and readable string manipulation code.

Consider the following code:

Program 1:

std::string operator"" _str(const char* str, std::size_t len)
    return std::string(str, len);

int main() {
    auto x = "hello"_str;
    std::cout << x << std::endl;
    return 0;


  • This code defines a user-defined literal operator, which allows a programmer to use a custom suffix (in this case, "_str") to indicate a string is to be treated as a std::string.
  • The operator takes two parameters, a pointer to a constant char, "str", and a std::size_t, "len".
  • The operator converts the string to a std::string by using the std::string constructor, which takes two arguments, a pointer to a char and a size_t, representing the start and the length of the string.
  • In the main function, the code declares a variable "x" and assigns it the value of "hello" by using the "_str" suffix after the string "hello". The "_str" is the suffix which we defined in our user-defined operator.
  • Finally, the program uses the "std::cout" function to print the value of x to the console. This will output the value of "hello".

Program Output:

User-defined literals

Program 2:

#include <iostream>

class Length {
    double value;
    Length(double v) : value(v) {}

Length operator"" _m(long double v) {
    return Length(v);
Length operator"" _cm(long double v) {
    return Length(v/100);
Length operator"" _mm(long double v) {
    return Length(v/1000);

int main() {
    Length x = 10.5_m;
    Length y = 1050.0_cm;
    Length z = 1050000.0_mm;
    std::cout << x.value << "m" << std::endl;
    std::cout << y.value << "m" << std::endl;
    std::cout << z.value << "m" << std::endl;
    return 0;


  • This program defines a C++ class called "Length", which has a single member variable "value" of type double.
  • It also defines three operator overloads for the class: "operator"" _m", "operator"" _cm", and "operator"" _mm".
  • These operators allow the user to create Length objects by appending the unit of measurement (meters, centimeters, or millimeters) as a suffix to a number.
  • In the main function, it creates three Length objects: x, y, and z.
  • The first object, x, is created by appending "_m" to the number 10.5, which is equivalent to calling the operator "" _m(10.5) and passing the resulting object to the constructor of class Length.
  • The second object, y, is created by appending "_cm" to the number 1050, which is equivalent to calling the operator "" _cm(1050) and passing the resulting object to the constructor of class Length.
  • The third object, z, is created by appending "_mm" to the number 1050000, which is equivalent to calling the operator "" _mm(1050000) and passing the resulting object to the constructor of class Length.
  • Finally, the program prints out the value of each object x, y, and z, followed by the unit of measurement "m" (for meters).
  • The first line is the value of variable x, which is initialized to 10.5_m. The operator "" _m converts the value 10.5 to a Length object with the value of 10.5.
  • The second line is the value of variable y, which is initialized to 1050_cm. The operator "" _cm converts the value 1050 to a Length object with the value of 10.5 (1050 / 100 = 10.5).
  • The third line is the value of variable z, which is initialized to 1050000_mm. The operator "" _mm converts the value 1050000 to a Length object with the value of 1050 (1050000 / 1000 = 1050).

This example demonstrates how user-defined literals can be used to create a custom measurement unit type that is more expressive and readable than using built-in types and conversion functions.

Program Output:

User-defined literals


  • In conclusion, user-defined literals are a powerful feature in C++11 that allow developers to create custom syntax for their programs.
  • They make code more readable and expressive by allowing developers to create custom operators with meaning specific to their domain.
  •  User-defined literals can be used for various types, such as converting angles from degrees to radians, converting C-style strings to std::string, or for any other use case that requires a custom syntax. T
  • hey are easy to define and use and can greatly improve the readability of your code.