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Use of Labels - goto

Use of Labels - goto

In this lesson you'll study how a program execution can be controlled with labels.

We'll cover the following...

Introduction #

A label is a sequence of characters that identifies a location within a code. A code line which starts with a for, switch, or select statements can be preceded with a label of the form:

IDENTIFIER:
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This is the first word ending with a colon : and preceding the code (gofmt puts it on the preceding line).

Use of labels in Go

Let’s look at an example of using a label in Go:

Go (1.6.2)
package main
import "fmt"
func main() {
    LABEL1:                           // adding a label for location
    for i := 0; i <= 5; i++ {         // outer loop
        for j := 0; j <= 5; j++ {         // inner loop
            if j == 4 {
                continue LABEL1                   // jump to the label
            }
            fmt.Printf("i is: %d, and j is: %d\n", i, j)
        }
    }
}

As you can see, we made a label LABEL1 at line 5. At line 6, we made an outer loop: for i := 0; i <= 5; i++ that will iterate 5 times. At line 7, we made an inner loop: for j := 0; j <= 5; j++ that will iterate 5 times for each i. You may have noticed that we added continue LABEL1 at line 9. The execution will jump to the label ...