# Functions

This is a simple Go program that defines two functions for addition and demonstrates their usage in the main function.

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

// Function plus takes two integers (a and b) as parameters and returns their sum.
func plus(a int, b int) int {
    return a + b
}

// Function plusPlus takes three integers (a, b, and c) as parameters and returns their sum.
func plusPlus(a, b, c int) int {
    return a + b + c
}

// The main function, which serves as the entry point for the program.
func main() {
    // Calling the plus function with arguments 1 and 2, storing the result in the variable "res".
    res := plus(1, 2)
    
    // Printing the result of the addition operation.
    fmt.Println("1+2 =", res)

    // Calling the plusPlus function with arguments 1, 2, and 3, storing the result in the variable "res".
    res = plusPlus(1, 2, 3)
    
    // Printing the result of the addition operation.
    fmt.Println("1+2+3 =", res)
}
```

#### Output

```
1+2 = 3
1+2+3 = 6
```

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

1. **Function Declarations:**
   * `plus(a int, b int) int`: This function takes two integers (`a` and `b`) as parameters and returns their sum.
   * `plusPlus(a, b, c int) int`: This function takes three integers (`a`, `b`, and `c`) as parameters and returns their sum.
2. **Main Function:**
   * `main()`: This is the entry point of the program.
   * `res := plus(1, 2)`: Calls the `plus` function with arguments 1 and 2, and stores the result in the variable `res`.
   * `fmt.Println("1+2 =", res)`: Prints the result of the addition operation.
   * `res = plusPlus(1, 2, 3)`: Calls the `plusPlus` function with arguments 1, 2, and 3, and stores the result in the variable `res`.
   * `fmt.Println("1+2+3 =", res)`: Prints the result of the addition operation.