Basic Structure of a C++ program | C++ tutorial

Today we will see how we will write C++ programs. and try to understand some basic concept of C++ in detail. so let's write a program in C++. and then we will understand the meaning of each and every line of our program.

Our first C++ program:

#include<iostream>

using namespace std;

int main(){

cout<<"hello C++"<<endl;

}

so let's understand the structure of our program.

the very first line is :

#include<iostream>

so basically what it is?

#include is a preprocessor directive that tells it to paste in the contents of the header file into the stream of C++ code that is fed to the compiler.

iostream stands for standard input output stream. this is basically a header file, inside this file there are different kind of functions and classes, which we use in our programs. this header file makes us able to send and receive data.

second line is:

using namespace std;

this line declares that classes and functions of the standard library can be used directly in the code. if you don't write this line then  the structure of code will get change and now you have to write the same program like this:

#include<iostream>

int main(){

std:cout<<"hello C++"<<endl;

}

third line is:

int main()

it is a function named "main". we will learn about function later. till now just understand that every program must have a main() function.

int main() means there is function named "main", whose return type is "int". we will see all these things in detail. so don't be panic.

next line is:

cout<<"hello C++"<<endl;

this line will print hello C++ on the screen after executing the code. so to print any thing on screen we will use cout<<thing which we want to print<<endl;

endl means end of line.

basically cout is an object(we will learn about object later). which is used for send output to the screen.

Output: