The document provides an overview of functions in the C programming language, explaining that they are blocks of code that execute when called, promoting modularity and code reusability. It highlights predefined functions such as main() and printf(), and illustrates how to declare and call user-defined functions with examples. The document also includes code snippets demonstrating the execution of functions and calculating sums.

1. An
Overview
By,
RANJAN V
Asst. Professor,
Dept. of AIML,
JNNCE

2. C Functions
“A function is a block of code which only runs when it is called.”
● A function in C is a set of statements that when called perform some
specific task.
● It is the basic building block of a C program that provides modularity
and code reusability.
● The programming statements of a function are enclosed within { }
braces, having certain meanings and performing certain operations.

3. Predefined Functions
main() is a function, which is used to execute code, and printf() is a function;
used to output/print text to the screen:
int main() {
printf("Hello World!");
return 0;
}

4. Create a Function
To create (often referred to as declare) your own function, specify the
name of the function, followed by parentheses () and curly brackets
{}:
Syntax:
void myFunction() {
// code to be executed
}

5. Call a Function
Declared functions are not executed immediately. They are "saved for later use",
and will be executed when they are called.
In the following example, myFunction() is used to print a text (the action),
when it is called:

6. Example
void myFunction() {
printf("I just got executed!");
}
int main() {
myFunction(); // call the function
return 0;
}

7. Calculate the Sum of Numbers
void calculateSum() {
int x = 5;
int y = 10;
int sum = x + y;
printf("The sum of x + y is: %d", sum);
}
int main() {
calculateSum(); // call the function
return 0;}
https://www.programi
z.com/online-compiler
/8uynCFmMSHVSg

8. EXAMPLE 1:

9. EXAMPLE 2:
https://www.programiz.com/online-
compiler/8apOTqMXaewD8

10. EXAMPLE 3:
https://www.programiz.com/online-compiler/
5Sq2tjqj56MSc