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++

Hello World Program in C++

The steps for “Hello World” C++ program are as follows:

  1. Write a C++ code given below in an editor.
  2. Save the file with .cpp
  3. Compile the code using C++ compiler or using online IDE.
  4. Check the output of the code.

“Hello World” program is considered as most basic and first program while learning any technology or language. In this program, user only prints “Hello World” statement to the screen.

Code:

// "Hello World" Program in C++
#include<iostream>
using namespace std;
int main()
{
     cout<<"Hello World";
     return 0;
}

Output:

Hello World

Let us understand the above program line by line

  1. // "Hello World" Program in C++
    • In C++, any statement starts with ‘//’ is called a comment line.
    • Comment line is not taken into consideration by compiler i.e. compiler don’t consider this line while compilation.
    • Comment is generally used to specify author name or to specify the meaning/logic of any statement.
    • In C++, comments are given to single line statement and multiline statements.
      1. Single line comments // statements
      1. Multiline comments /*      statements */
  1. #include<iostream>
  • The statement starts with (#) are called as directives in C++.
  • Here, #include tells compiler to add include the header file which is “iostream.”
  • The iostream header file provides inbuilt input/output objects and functions. We can use the “cout” object only by including “iostream” header file.

  1. using namespace std;
  • This statement add the “std” namespace into the current file.
  • Add an entire “std” package sometimes consider as bad practice because it imports all declarations from namespace “std” that contains the declaration for the cout and cin objects. Hence “std::cout” is consider as a good practice to use in program instead of importing entire “std” namespace into the code.
  1. int main()
  • In “int main ()” defines the function definition where main () is the function and int is the return type of function.
  • The main () is consider as the starting point of the program and compiler starts the execution from the main () function only. And hence it is important to write main () function in every C++ program.
  • As the return type of main () function is int, function will return an integer value from the function and the value that this main () functions return we see that in further article.
  1. { and }
  • The statements written inside these curly brackets { } are called the function body.
  • Here, “{” represents the starting of the function and “}” represents the closing of the function.
  1. cout<<"Hello World";
  • This statement tell compiler to print "Hello World" to output screen.
  • Here, cout is the object of ostream class which we included I current program using “iostream” header file.
  • The cout object is used to print the statement on the screen and it must use with << operator.
  • The cout print the statement to output screen using << operator and it print the string written inside the " " double quotes.
  • The above statement cout<<"Hello World"; is terminated with semicolon which represents the end of the statement. In C++, every statement must be terminated with semicolon (;).
  1. return 0;
  • This is also a statement in C++ and hence it is also terminated with semicolon (;).
  • To return a value from the function, return statement is used in C++.
  • The “return 0” statement is returning value 0 which is of type int and this int type is similar to the function return type.



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