Writing First C++ Program - Hello World Example
Last Updated : 23 Apr, 2025
The "Hello World" program is the first step towards learning any programming language and is also one of the most straightforward programs you will learn. It is the basic program that demonstrates the working of the coding process. All you have to do is display the message "Hello World" on the output screen.
C++ Hello World Program
This program helps you to learn the fundamental structure of a program, and it also learn the basic syntax for the programming language.
C++ // Necessary header files for input output functions #include <iostream> using namespace std; // main() function: where the execution of // C++ program begins int main() { // This statement prints "Hello World" cout << "Hello World"; return 0; } To write and run C++ programs, you need to set up the local environment on your computer. Refer to the complete article Setting up C++ Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your C++ programs.
Let us now understand every line and the components of the above program.
The comment are used to display additional information about the program that do not contain any programming logicand are not the part of executable program and are purely used for documentation and provide explanation or notes about the code. When a comment is encountered by a compiler, the compiler simply skips that line of code.
C++ // C++ program to print "Hello World"
Preprocessor Directives
The #include is a preprocessor directive that tells the compiler to include the content of a file in the source code. For example, #include<iostream> tells the compiler to include the input-output library which contains all C++'s input/output library functions.
C++ In C++ language header file is a file that contains features like functions, data types, macros, etc that can be used by any other C program by including that particular header file using “#include” preprocessor. Header files generally ends with the .h extension although in modern C++ many header files do not have the .h extension
C++ // header file without .h extension #include <iostream> // header file with .h extension #include<string.h>
Namespace
In C++ namespaces are used to group logically related functions, variables and other entities to avoid name conflicts. is used to import the entity of the std namespace into the current namespace of the program. It is basically the space where all the inbuilt features of C++ are declared. For example, std::court.
C++ Main Function
The main() function is the entry point of every C++ program when the program is executed the code written in the main functions is executed first. The opening braces '{' indicates the beginning of the main function and the closing braces '}' indicates the ending of the main function.
C++ int main() { //Program code } Output Statement
The cout is a output statement in C++ that is used to display output on the console screen. Everything followed by the character << in double quotes " " is displayed on the output screen. The semi-colon character at the end of the statement is used to indicate that the statement is ending there.
C++ Return Statement
The return statement is used to return a value from a function and indicates the finishing of a function. Here, it is used to sent the signal of successful execution of the main function.
C++ Also, as you can see, the cout and the return statement have been indented or moved to the right side. This is done to make the code more readable. We must always use indentations and comments to make the code more readable.
While writing C++ programs we must follow the standard practices of indentation, documentation and program maintenance to write clean understandable and easily manageable code.
Similar Reads
C++ Tutorial | Learn C++ Programming C++ is a popular programming language that was developed as an extension of the C programming language to include OOPs programming paradigm. Since then, it has become foundation of many modern technologies like game engines, web browsers, operating systems, financial systems, etc.Features of C++Why
5 min read
Setting up C++ Development Environment C++ is a general-purpose programming language and is widely used nowadays for competitive programming. It has imperative, object-oriented, and generic programming features. C++ runs on lots of platforms like Windows, Linux, Unix, Mac, etc. Before we start programming with C++. We will need an enviro
8 min read
Writing First C++ Program - Hello World Example The "Hello World" program is the first step towards learning any programming language and is also one of the most straightforward programs you will learn. It is the basic program that demonstrates the working of the coding process. All you have to do is display the message "Hello World" on the outpu
4 min read
C++ Variables In C++, variable is a name given to a memory location. It is the basic unit of storage in a program. The value stored in a variable can be accessed or changed during program execution.Creating a VariableCreating a variable and giving it a name is called variable definition (sometimes called variable
4 min read
C++ Data Types Data types specify the type of data that a variable can store. Whenever a variable is defined in C++, the compiler allocates some memory for that variable based on the data type with which it is declared as every data type requires a different amount of memory.C++ supports a wide variety of data typ
7 min read
Operators in C++ C++ operators are the symbols that operate on values to perform specific mathematical or logical computations on given values. They are the foundation of any programming language.Example:C++#include <iostream> using namespace std; int main() { int a = 10 + 20; cout << a; return 0; }Outpu
9 min read
Basic Input / Output in C++ In C++, input and output are performed in the form of a sequence of bytes or more commonly known as streams.Input Stream: If the direction of flow of bytes is from the device (for example, Keyboard) to the main memory then this process is called input.Output Stream: If the direction of flow of bytes
5 min read
Decision Making in C++
Decision Making in C (if , if..else, Nested if, if-else-if )In C, programs can choose which part of the code to execute based on some condition. This ability is called decision making and the statements used for it are called conditional statements. These statements evaluate one or more conditions and make the decision whether to execute a block of code or n
7 min read
C++ if StatementThe C++ if statement is the most simple decision-making statement. It is used to decide whether a certain statement or block of statements will be executed or not executed based on a certain condition. Let's take a look at an example:C++#include <iostream> using namespace std; int main() { int
3 min read
C++ if else StatementThe if statement alone tells us that if a condition is true it will execute a block of statements and if the condition is false, it won’t. But what if we want to do something else if the condition is false. Here comes the C++ if else statement. We can use the else statement with if statement to exec
3 min read
C++ if else if LadderIn C++, the if-else-if ladder helps the user decide from among multiple options. The 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. I
3 min read
C++ Nested if-else StatementNested if-else statements are those statements in which there is an if statement inside another if else. We use nested if-else statements when we want to implement multilayer conditions (condition inside the condition inside the condition and so on). C++ allows any number of nesting levels.Let's tak
3 min read
Switch Statement in C++In C++, the switch statement is a flow control statement that is used to execute the different blocks of statements based on the value of the given expression. It is an alternative to the long if-else-if ladder which provides an easy way to execute different parts of code based on the value of the e
5 min read
Jump statements in C++Jump statements are used to manipulate the flow of the program if some conditions are met. It is used to terminate or continue the loop inside a program or to stop the execution of a function.In C++, there is four jump statement:Table of Contentcontinue Statementbreak Statementreturn Statementgoto S
4 min read
C++ Loops
C++ LoopsIn C++ programming, sometimes there is a need to perform some operation more than once or (say) n number of times. For example, suppose we want to print "Hello World" 5 times. Manually, we have to write cout for the C++ statement 5 times as shown.C++#include <iostream> using namespace std; int
7 min read
for Loop in C++In C++, for loop is an entry-controlled loop that is used to execute a block of code repeatedly for the given number of times. It is generally preferred over while and do-while loops in case the number of iterations is known beforehand.Let's take a look at an example:C++#include <bits/stdc++.h
6 min read
C++ While LoopIn C++, the while loop is an entry-controlled loop that repeatedly executes a block of code as long as the given condition remains true. Unlike the for loop, while loop is used in situations where we do not know the exact number of iterations of the loop beforehand as the loop execution is terminate
3 min read
C++ do while LoopIn C++, the do-while loop is an exit-controlled loop that repeatedly executes a block of code at least once and continues executing as long as a given condition remains true. Unlike the while loop, the do-while loop guarantees that the loop body will execute at least once, regardless of whether the
4 min read
Range-Based for Loop in C++In C++, the range-based for loop introduced in C++ 11 is a version of for loop that is able to iterate over a range. This range can be anything that is iteratable, such as arrays, strings and STL containers. It provides a more readable and concise syntax compared to traditional for loops.Let's take
3 min read
Functions in C++ A function is a building block of C++ programs that contains a set of statements which are executed when the functions is called. It can take some input data, performs the given task, and return some result. A function can be called from anywhere in the program and any number of times increasing the
9 min read