> For the complete documentation index, see [llms.txt](https://ineelhere.gitbook.io/code-with-go/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ineelhere.gitbook.io/code-with-go/14-variadic-functions.md).

# Variadic Functions

This Go program demonstrates the use of variadic functions and the spread operator.

```go
// Importing the "fmt" package, which provides functions for formatted I/O.
import "fmt"

// Function sum takes a variable number of integers as parameters using the ellipsis (...) syntax.
// It prints the input numbers and calculates their sum.
func sum(nums ...int) {
    // Print the input numbers.
    fmt.Print(nums, " ")

    // Initialize a variable to store the sum.
    total := 0

    // Iterate over the input numbers and calculate the sum.
    for _, num := range nums {
        total += num
    }

    // Print the calculated sum.
    fmt.Println(total)
}

// The main function, which serves as the entry point for the program.
func main() {
    // Calling the sum function with two integer arguments (1 and 2).
    sum(1, 2)

    // Calling the sum function with three integer arguments (1, 2, and 3).
    sum(1, 2, 3)

    // Creating a slice of integers and passing it to the sum function using the spread operator (...).
    nums := []int{1, 2, 3, 4}
    sum(nums...)
}
```

#### Output

```
[1 2] 3
[1 2 3] 6
[1 2 3 4] 10
```

Now, let's break down the code and explain each part:

1. **Function Declarations:**
   * `sum(nums ...int)`: This function takes a variable number of integers using the ellipsis (...) syntax. It prints the input numbers and calculates their sum.
2. **Main Function:**
   * `main()`: This is the entry point of the program.
   * `sum(1, 2)`: Calls the `sum` function with two integer arguments (1 and 2).
   * `sum(1, 2, 3)`: Calls the `sum` function with three integer arguments (1, 2, and 3).
   * `nums := []int{1, 2, 3, 4}`: Creates a slice of integers.
   * `sum(nums...)`: Calls the `sum` function with the elements of the `nums` slice passed as individual arguments using the spread operator `...`.