Functions

🔧 What Is a Function in Programming?

A function is a reusable block of code designed to perform a specific task. Instead of writing the same code repeatedly, you can define it once in a function and "call" it whenever needed.

---

✅ Why Use Functions?

• Reusability: Write once, use many times.

• Clarity: Makes code easier to read and understand.

• Organization: Helps break large programs into smaller, manageable pieces.

• Debugging: Easier to find and fix errors in isolated blocks of code.

---

🧠 How Functions Work

A basic function has:

1. Name – to identify the function.

2. Parameters (optional) – input values.

3. Code block – what the function does.

4. Return value (optional) – the result it gives back.

---

1. Basic Function Without Parameters

def who_i_am():
    name = "KT"
    age = 25
    gpa = 2.8
    print("My name is " + name + " and I am " + str(age) + " years old.")

who_i_am()

• def: Defines a function named who_i_am.

• Inside the function, variables are set and a message is printed.

• who_i_am() calls the function and displays:

---

2. Function with One Parameter

def add_one_hundred(num):
    print(num + 100)

add_one_hundred(200)

• Accepts one input (num), adds 100 to it, and prints the result.

• Output:

---

3. Function with Two Parameters

def add(x, y):
    print(x + y)

add(10, 20)

• Takes two inputs and prints their sum.

• Output:

---

4. Function with Return Value

def multiply(x, y):
    return(x * y)

print(multiply(10, 20))

• Multiplies x and y, then returns the result using return.

• print() displays the returned value.

• Output:

---

✅ Summary

• Functions organize code into reusable blocks.

• Use parameters to pass data in.

• Use return to send data out.

• Calling a function runs its code.

#!/bin/python3

#Functions
def who_i_am():
	name = "KT"
	age = 25
	gpa = 2.8
	print("My name is " + name + " and I am " + str(age) + " years old.")
who_i_am()	



#adding parameters
def add_one_hundred(num):
	print(num + 100)
add_one_hundred(200)



#multiple parameters
def add(x,y):
	print(x + y)
add(10,20)


def multiply(x,y):
	return(x * y)
print(multiply(10,20))