Header files in dev-C. Ask Question Asked 11 years ago. Active 2 years. I'm trying to add an header file to dev-C but when I compile it it doesn't work. Mar 28, 2013 In new versions of dev c compiler automatically adds one source file to project. If there is no any existing source file simply add new file By chossing new file option from file menu. Type the following code and save the file. I saved file as 'main.cpp' its your chooice whatever you name it.
C++ Syntax
Let's break up the following code to understand it better:
Example
Header Files Of Dev C 5
#include <iostream>
using namespace std;
int main() {
cout << 'Hello World!';
return 0;
}
Run example »using namespace std;
int main() {
cout << 'Hello World!';
return 0;
}
Example explained
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.Reason 9 free download. 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 appear 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 together with the insertion operator (<<
) 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 been written as:int main () { cout << 'Hello World! '; return 0; }
Remember: The compiler ignores white spaces. However, multiple lines makes the code more readable.
Line 6:
return 0
ends the main function.Line 7: Do not forget to add the closing curly bracket
}
to actually end the main function.Omitting Namespace
You might see some C++ programs that runs without the standard namespace library. 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;
}
Run example »int main() {
std::cout << 'Hello World!';
return 0;
}
C++ Header File Example
It is up to you if you want to include the standard namespace library or not.