Function Overview | 點燈坊

We can use func keyword to define a function.

Version

Golang 1.17.7

main.go

package main

import "fmt"

func main() {
    result := add(1, 2)
    fmt.Println(result)
}

func add(x, y int) int {
    return x + y
}

Line 1

package main

Declare main package for the executable program.

Line 3

import "fmt"

Import fmt package for using fmt.Println().

Line 5

func main() {
    result := add(1, 2)
    fmt.Println(result)
}

main() is a special function and it’s the entry point of the executable program.

Go is not an OOP-only language. We can define function directly
func : define a function with func keyword
:= : define a variable without type. The type is inferred automatically by Type Inference
fmt.Println : print out the result

Line 10

func add(x, y int) int {
    return x + y
}

add() is a user-defined function.

x, y int : parameter x and y are all type int. We can ignore to declare type int on the first parameter
func add() int : declare return type int of the function

We don’t have to define add() before using main()

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