C++ Syntax C-PLUS-PLUS
- C++ Introduction
- C++ Syntax
- C++ Output (cout <<)
- C++ Comments
- C++ Variables
- C++ User Input
- C++ Data Types
- C++ Operators
- C++ Strings
- C++ Math
- C++ Booleans
- C++ If Else
- C++ Switch
- C++ While Loop
- C++ Do/While Loop
- C++ For Loop
- C++ Break and Continue
- C++ Arrays
- C++ References
- C++ Pointers
- C++ Functions
- C++ Functions Parameters
- C++ Function Overloading
- C++ OOP
- C++ Classes and Objects
- C++ Class Methods
- C++ Constructors
- Destructors in C++
- C++ Access Specifiers
- C++ Encapsulation
- C++ Inheritance
- C++ Polymorphism
- C++ Files
- C++ Exception Handling
C++ Syntax
C++ Syntax
using namespace std;
int main() {
cout << "Hello World!";
return 0;
}
Explanation:
Line 1: #include <iostream>
is a header file library that lets us work with input and output objects, such as cout
(used in line 5). Header files add functionality to C++ programs.
Line 2: using namespace std
means that we can use names for objects and variables from the standard library.
Don't worry if you don't understand how #include <iostream>
and using namespace std
works. Just think of it as something that (almost) always appears in your program.
Line 3: A blank line. C++ ignores white space.
Line 4: Another thing that always appears in a C++ program, is int main()
. This is called a function. Any code inside its curly brackets {}
will be executed.
Line 5: cout
(pronounced "see-out") is an object used to output/print text. In our example, it will output "Hello World".
Note: Every C++ statement ends with a semicolon ;
.
Note: The body of int main()
could also be written as:
int main () { cout << "Hello World! "; return 0; }
Remember: The compiler ignores white spaces. However, multiple lines make the code more readable.
Line 6: return 0
ends the main function.
Omitting Namespace
The using namespace std
line can be omitted and replaced with the std
keyword, followed by the ::
operator for some objects:
Example
#include <iostream>
int main() {
std::cout << "Hello World!";
return 0;
}
Output:
Hello World!
It is up to you if you want to include the standard namespace library or not.