Functions

A function is just a set of instructions with a name (although the name is optional)

The main function is a special function - execution starts from here. For example

func main() {
	fmt.Printf("Hello, World!")
}

You don’t explicitly call the main function. For all other functions, you need to call them. This is how you would do it with another function

func PrintHello() {
	fmt.Printf("Hello World!")
}

func main() {
	PrintHello()
}

Function declaration - starts with func keyword in Go

Why do we need functions?

• Reusability - no need to rewrite code over and over again. You just need to declare the function once but call it multiple times.
• Good for commonly used operations
• Abstraction over computation - you can use functions to think from a higher level of abstraction (hiding details within the function - you can treat the function as a black box)
• Improved understandability, which is key for design

Use meaningful names for functions

Function Parameters

Functions may need some input data to perform computation - so these are passed to the functions inside parantheses.

Parameters are listed in parantheses after the function name. For example,

func foo(x int, y int) {
	fmt.Printf(x * y)
}
// calling the function
func main() {
	foo(2, 3)
}

Arguments are supplied when you call the function.

Note the order of variable name and its type is different from Java.