How to create your own header file in C++
Hello, Coders! In this C++ tutorial, we will discuss and learn about the header files in C++ and how to create our own header files easily.
Header Files in C++
- C++ language has a large collection of libraries of predefined functions. The header files contain various types of predefined standard library functions. It contains the function definition, data type definition, and macros.
- The predefined functions can be used by simply including the header files with the preprocessing directive #include. By using the preprocessing directive, we can import the functions and use them anywhere in the program.
We can divide the header files into two types:
1. Predefine/System header files: The header files are already predefined or available in the C++ compiler, to use the functions we just need to import them in our program.
2. User-defined header file: These files are defined/designed by the user themself and can be used or imported by using the preprocessor directive #include.
Syntax:
#include <header_filename.h> //or #include "header_filename.h"
How to Create a Header file in C++
- Instead of using the predefined functions, we can create our own header files and import them to any program. It increases the code readability and functionality.
- Let’s consider a problem where we want to calculate the sum of digits. Since there is no predefined function for the operations in the standard C++ library, we will create it by ourselves.
Step-1:
Open any text editor or IDE and write your C++ code. Then save it with a “.h” extension.
Example: sumdigit.h
int digitSum(int number) { int sum = 0; while (number != 0) { sum = sum + number % 10; number = number / 10; } return sum; }
Step-2:
Locate the saved file in your disk and move it to the include directory inside the bin folder of your C++ compiler. In the case of the Linux system, move the header file to /usr/lib/gcc/include directory.
Step-3:
Write a C++ program in your preferred IDE. Before defining the main method, we will import the functions by mentioning the header files to the program. Include our newly created header file as #include<sumdigit.h> or #include”sumdigit.h” along with other header files.
#include <iostream> #include <sumdigit.h> using namespace std; int main() { int digit; cout<<"Enter a Digit to get the Sum: " <<endl; cin>>digit; int sumofdigit = digitSum(digit); cout<<"The Sum of digit " << digit << " is: " << sumofdigit <<endl; return 0; }
Step-4:
Save the file with the “.cpp” extension, compile and run the program to get the sum of the given digit.
Output:
Enter a Digit to get the Sum: 867 The Sum of digit 867 is: 21
Hope this C++ tutorial has helped you to understand the concept of header files and create user-defined header files in C++.
Happy Coding!!
You can also read, Move files from directories in C++
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