Functions in Go
A function is a block of code that’s assigned a name, and contains some instructions.
In the “Hello, World!” example we created a main
function, which is the entry point of the program.
package main
import "fmt"
func main() {
fmt.Println("Hello, World!")
}
That’s a special function.
Usually we define functions with a custom name:
func doSomething() {
}
and then you can call them, like this:
doSomething()
A function can accept parameters, and we have to set the type of the parameters like this:
func doSomething(a int, b int) {
}
doSomething(1, 2)
a
and b
are the names we associate to the parameters internally to the function.
A function can return a value, like this:
func sumTwoNumbers(a int, b int) int {
return a + b
}
result := sumTwoNumbers(1, 2)
Note we specified the return value type
A function in Go can return more than one value:
func performOperations(a int, b int) (int, int) {
return a + b, a - b
}
sum, diff := performOperations(1, 2)
It’s interesting because many languages only allow one return value.
Any variable defined inside the function is local to the function.
A function can also accept an unlimited number of parameters, and in this case we call it variadic function:
func sumNumbers(numbers ...int) int {
sum := 0
for _, number := range numbers {
sum += number
}
return sum
}
total := sumNumbers(1, 2, 3, 4)
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