C++ is a popular cross-platform language that can be used to create high-performance applications - operating systems, browsers, video-games, art applications and so on. C++ was derived from C, and is largely based on it. A C++ program is a collection of commands or statements.
Below is a simple program template.
#include <iostream>
using namespace std;
int main()
{
return 0;
}
For now, remember that the entry point of every C++ program is the main() function, irrespective of what the program does. Curly brackets { } indicate the beginning and end of a function, which can also be called the function's body. The information inside the brackets indicates what the function does when executed.
Let's output "Hello world!" to the screen!
To do that, we will add cout << "Hello world!";
line to our main() function body:
#include <iostream> //header file included iostream >> for standrd input and out header
using namespace std;
int main() //entry point of the program
{
cout << "hello world";
return 0;
}
cout is used to perform output on the standard output device which is usually the display screen.
cout is used in combination with the insertion operator <<.
Note that you can add multiple insertion operators after cout.
In C++, the semicolon is used to terminate a statement. Each statement must end with a semicolon. It indicates the end of one logical expression.
C++ offers various headers, each of which contains information needed for programs to work properly.
We have already seen the standard header on our first C++ program:
C++ offers various headers, each of which contains information needed for programs to work properly.
We have already seen the standard <iostream>
header on our first C++ program:
#include is used for adding a standard or user-defined header files to the program.
The <iostream>
header defines the standard stream objects that input and output data.
A namespace is a declarative region that provides a scope to the identifiers (names of elements) inside it.
In our code, the line using namespace std;
tells the compiler to use the std (standard) namespace:
The std
namespace includes features of the C++ Standard Library.
Comments are explanatory statements that you can include in the C++ code to explain what the code is doing.
The compiler ignores everything that appears in the comment, so none of that information shows in the result.
A comment beginning with two slashes (//) is called a single-line comment. The slashes tell the compiler to ignore everything that follows, until the end of the line.
#include <iostream>
using namespace std;
int main()
{
// prints "Hello world"
cout << "Hello world!";
return 0;
}
```When the above code is compiled, it will ignore the **// prints "Hello world"** statement**.**