C Functions
What are Functions in C?
A function is a block of code that performs a specific task.
Functions help divide a large program into smaller and manageable parts.
They improve code reusability, readability, and maintenance.
Instead of writing the same code multiple times, a function can be called whenever needed.
Example
void greet()
{
printf(“Welcome to C Programming”);
}
Explanation
• greet() is the function name.
• void indicates that the function does not return any value.
• The function displays a welcome message.
• The function can be called whenever required.
Why Functions are Important?
Functions are important because they:
• Reduce code repetition.
• Improve code readability.
• Make programs easier to maintain.
• Help divide large programs into smaller modules.
• Increase code reusability.
Types of Functions in C
C provides two types of functions:
• Library Functions
• User-Defined Functions
Library functions are predefined functions provided by C.
User-defined functions are created by the programmer according to requirements.
Library Functions
Library functions are predefined functions provided by the C Standard Library.
These functions are ready to use and help perform common tasks.
Examples of library functions:
• printf()
• scanf()
• strlen()
• sqrt()
• pow()
Example
#include <stdio.h>
int main()
{
printf(“Hello World”);
return 0;
}
Explanation
• printf() is a library function.
• It is used to display output on the screen.
• The function is available through the stdio.h header file.
• No need to create the function because it is already provided by C.
User-Defined Functions
User-defined functions are functions created by the programmer.
They are used when a specific task needs to be performed repeatedly.
These functions improve code reusability and organization.
Example
#include <stdio.h>
void greet()
{
printf(“Welcome to C Programming”);
}
int main()
{
greet();
return 0;
}
Explanation
• greet() is a user-defined function.
• The function contains code to display a welcome message.
• greet(); is used to call the function.
• When the function is called, the statements inside the function are executed.
• User-defined functions help avoid writing the same code repeatedly.
Advantages of Functions
• Reduce code duplication.
• Improve code readability.
• Make debugging easier.
• Increase code reusability.
• Help organize large programs into smaller modules.
Example Program
Program
#include <stdio.h>
void greet()
{
printf(“Welcome to C Programming”);
}
int main()
{
greet();
return 0;
}
Output
Welcome to C Programming
Explanation
• #include <stdio.h> includes the standard input/output library.
• greet() is a user-defined function.
• printf() displays the message on the screen.
• greet(); calls the function.
• When the function is called, the statements inside the function are executed.
• return 0; ends the program successfully.
Key Points
• Functions are blocks of code that perform specific tasks.
• Functions improve code reusability and readability.
• C provides Library Functions and User-Defined Functions.
• Library functions are predefined by C.
• User-defined functions are created by programmers.
• Functions help organize large programs into smaller modules.