How to create and use functions in Go?

To create and use functions in Go, you can follow these steps:

Function Declaration: Start by declaring a function using the func keyword followed by the function name, parameter list, and return type. For example:

func sayHello() {
    fmt.Println("Hello!")
}

Function Parameters and Return Types: You can define parameters within parentheses after the function name, separated by commas. And if your function returns a value, specify the return type after the parameter list using the func functionName() returnType syntax. For example:

func sum(a int, b int) int {
    return a + b
}

Function Call: To call a function, simply use its name followed by parentheses. For example:

sayHello() // Call the sayHello function

result := sum(10, 5) // Call the sum function and store the result
fmt.Println(result)

Function Arguments: When calling a function with parameters, pass the arguments inside the parentheses separated by commas. For example:

func printMessage(message string) {
    fmt.Println(message)
}

printMessage("Hello, World!") // Call the printMessage function with an argument

Function Multiple Return Values: Go functions can return multiple values. For example:

func calculate(a, b int) (int, int) {
    return a + b, a - b
}

sum, diff := calculate(10, 5) // Call the calculate function and use multiple return values
fmt.Println(sum, diff)

Note that you need to import the necessary packages to use built-in functions from the Go standard library.