C Functions

Functions in C are a group of statements that perform a single task. They serve to improve the readability, modularity, and reusability of code by dividing a program into pieces.

Key points about functions

Function Declaration
Function Definition
Function Calls

Function Declarations

A function is first declared before it can be used. The declaration indicates the return type, name, and parameters of the function.

Syntax:

return_type function_name(para_1, para_2){
  // block of the function
}

Function Definition

Function definitions include the implementation of the actual function.

Function Call

A function is invoked by name and then by parentheses.

Example:


            #include
            <stdio.h> 

            

            // Function declaration 

            void
            func(); 


            int
            main()
            { 


              func();
            // calling the function 

              return
            0;
            

            } 


            // Function definition 

            void
            func()
            { 

                printf("Execution Succesfull."); 

            }

Output

Execution Succesfull.

Types of functions

Library Functions
User Defined Functions

Library Functions

Library functions are previously defined functions in the C programming language. They are defined in header files.
Exp: printf(), scanf(), etc

User Defined Functions

User-defined functions are functions that the programmer defines to perform special jobs. The programmer defines such functions according to his or her requirements and can be utilized multiple times in the program.
Exp: Any function defined by the programmer.

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