C Functions

What is a Function?

A function is a block of code that performs a specific task.

Functions help organize code, reduce repetition, and make programs easier to understand.

Function Declaration (Prototype)

A function prototype tells the compiler about a function before it is used.

It defines the function name, return type, and parameters.

Function Definition

The function definition contains the actual code that runs.

Calling a Function

You call a function by using its name followed by parentheses.

Parameters and Arguments

Parameters are variables defined in the function, while arguments are the values passed to it.

Return Values

Functions can return values using the return statement.

The return type must match the function declaration.

Void Functions

If a function does not return a value, use void.

Passing Arrays to Functions

Arrays are passed to functions as pointers.

This means changes inside the function affect the original array.

Pass by Value vs Pointer

C uses pass-by-value by default, meaning a copy is passed.

To modify the original value, use pointers.

Why Functions are Important

Functions are essential for writing clean and reusable code.

• Reduce repetition
• Improve readability
• Make debugging easier

Common Mistakes

Be careful with these:

• Forgetting function prototypes
• Mismatched return types
• Not using pointers when needed

Practice

Create a function that takes two integers and returns their sum.

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