Overview

Goto statement allows unconditional jump to a labeled statement with in the same function . Below is the format of the goto statement

goto label
...
...
label: statement

The label can be valid go statement other than a keyword. As soon as the goto statement is encountered the control is transferred to the referred label and execution continues from there. The label is only visible inside the function where it has been declared. Any reference from outside the function will result in a compilation error.

Example

Let’s see a simple example of goto statement

package main
import "fmt"
func main() {
    learnGoTo()
}
func learnGoTo() {
    fmt.Println("a")
    goto FINISH
    fmt.Println("b")
FINISH:
    fmt.Println("c")
}

Output

a
c

In the above example we have a goto statement as

goto FINISH

The FINISH label is as below

FINISH:
    fmt.Println("c")

As soon as the program encounters the goto statement it jumps to the referred label. That is why below line never gets executed and b is never printed.

fmt.Println("b")

Both label and goto need to belong to same function otherwise it will raise compilation error. This is because scope of label is within the function in which it is declared as mentioned above. For example below program raises a compilation error

./main.go:11:7: label FINISH not defined
./main.go:17:1: label FINISH defined and not used

package main

import "fmt"

func main() {
	learnGoTo()
}

func learnGoTo() {
	fmt.Println("a")
	goto FINISH
	fmt.Println("b")

}

func test() {
FINISH:
	fmt.Println("c")
}

The label can be before goto statement as well. See below example. The program can be use to print all odd numbers before 10. Notice that label  START lies before goto here

package main
import "fmt"
func main() {
    learnGoTo()
}
func learnGoTo() {
    i := 0
    fmt.Println("here")
START:
    for i < 10 {
        if i%2 == 0 {
            i++
            goto START
        }  
        fmt.Println(i)
        i++
    }
}

Use of Goto is not recommended practice as readability is bad and is generally a source of lot of bugs too.  Any thing which is achieved using goto can be achieved using other go constructs