1. Introduction to Functions

1.1 What are Functions?

Functions are self-contained blocks of code that perform specific tasks. They are fundamental building blocks that help organize code, promote reusability, and make programs more modular and maintainable.

Benefits of Functions:

• Code Reusability: Write once, use multiple times
• Modularity: Break complex problems into smaller, manageable pieces
• Maintainability: Easier to debug, test, and modify
• Readability: Makes code more organized and understandable
• Abstraction: Hide implementation details from the caller

1.2 Python vs C Functions Comparison

Aspect	Python	C
Declaration	Not required	Function prototype usually required (unless defined before use)
Definition	def function_name():	return_type function_name() { }
Return Type	Dynamic (any type)	Must be explicitly declared
Parameters	Dynamic typing	Static typing required
Call Before Definition	Allowed	Requires prototype
Multiple Return Values	return a, b	Use pointers or structures

Python Example:

def add_numbers(a, b):
    return a + b

result = add_numbers(5, 3)
print(result)  # Output: 8

C Equivalent:

#include <stdio.h>

// Function declaration (prototype)
int add_numbers(int a, int b);

int main() {
    int result = add_numbers(5, 3);
    printf("%d\n", result);  // Output: 8
    return 0;
}

// Function definition
int add_numbers(int a, int b) {
    return a + b;
}