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++

C++ Comments

Comment/Remark

A Comment or a Remark is text that is ignored by the compiler yet is beneficial to programmers. Code is usually annotated with comments for future reference. They are treated as white space by the compiler. In testing, you may use comments to make particular lines of code inactive; however, the #if / #endif preprocessor directives are superior for this since you can surround code with comments but not nest them. Comments are a crucial aspect of excellent documentation.

  • A remark in computer programming is a programmer-readable explanation or annotation in a computer program's source code.
  • Comments are statements that the compiler and interpreter do not execute.

There are two types of Comments in C++:

1. Single Line Comment

Any sequence of characters after the / (two slashes) characters. This type of comment is terminated by a new line that is not immediately beyond the backslash. As a result, it is known as "single-line comment / remark".

Example of a program containing single line comment:

#include <iostream>
#include <bits/stdc++.h>  
using namespace std;  
int main()  
{  
 int a = 5; // a is a variable      
 cout<<”Value of a is: “<<a<<endl;
 return 0;         
} 

OUTPUT:

Value of a is : 5

Explanation:

In the above example of a code printing value of a variable having a single line comment “// a is a variable” in the sixth line of code.

2. Multiple Line Comment

The */ characters, followed by any sequence of characters (including new lines), then the /* (slash, asterisk) characters. This syntax is identical to that of ANSI C.

Example of a program containing multiple line comment:

#include <iostream>
#include <bits/stdc++.h>  
using namespace std;  
int main()  
{  
 /* declaring and   
 print the vale of the variable a. */   
 int a = 14;     
 cout<<"Value of a is: <<a<<endl;
 return 0;         
} 

OUTPUT:

Value of a is: 14

Explanation:

In the above example of a code printing value of a variable having multiple line comment ”/* declaring and print the value of the variable a. */” in  6th and 7th line of code.

NOTE: Comments can also be used to deactivate code, making it unavailable for execution. As an example:

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
int main() {
   cout << "JAVATPOINT ";
   // cout << "Hello world !";
   cout << "for C++"<<endl;
   return 0;
}

OUTPUT:

JAVATPOINT for C++

Explanation:

In the above example of code printing “JAVATPOINT for C++” in which 6th line containing single line comment which is deactivated, making it unavailable for execution.

Tip: Remember the comment shortcut; it can be really useful. It's Ctrl + / for Windows and Cmd + / for Mac in most coding editors.

What are the benefits of using comments?

  • If there are no comments on the program's intricacies, a person reading a huge code will be perplexed.
  • Comments are a means to provide extra description to a code to make it more understandable.
  • To make code more intelligible, comments might provide a description of an algorithm.
  • If code is to be reused over a lengthy period of time, comments might be useful for one-self as well.

NOTE: Comments should not be used to clarify badly written code written in English. Always write code that is well-structured and self-explanatory. Then there's the utilization of comments.



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