> For the complete documentation index, see [llms.txt](https://university-west.gitbook.io/programming-paradigms/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://university-west.gitbook.io/programming-paradigms/programming-fundamentals/functions.md).

# Functions

#### Functions/Methods in Computer Programming

In computer programming, functions or methods (the terms are often used interchangeably, though with some differences depending on the programming paradigm and language) are reusable blocks of code designed to perform a specific task. A function typically takes input (known as arguments or parameters), performs some operations on the input, and then returns an output. The main purpose of functions is to segment large programs into smaller, manageable, and reusable components. This enhances readability, makes maintenance easier, and helps avoid redundancy.

**Functions in Python**

A Python function is defined using the `def` keyword, followed by the function name and parentheses (`()`) which may include arguments. The code block within the function starts with a colon (`:`) and is indented.

**Example:**

```python
# Define a function in Python
def greet(name):
    return f"Hello, {name}!"

# Call the function
print(greet("Alice"))
```

Output:

```
Hello, Alice!
```

**Methods in C#**

In C#, a method is a code block containing a series of statements. Methods are defined within classes or structs, and they can perform operations and return values. Methods in C# are defined using the return type, the name of the method, and a pair of parentheses which can include parameters.

**Example:**

```csharp
using System;

class Program
{
    // Define a method in C#
    static string Greet(string name)
    {
        return $"Hello, {name}!";
    }

    static void Main(string[] args)
    {
        // Call the method
        Console.WriteLine(Greet("Bob"));
    }
}
```

Output:

```
Hello, Bob!
```


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