golang switch

If you want to evaluate cases in the Go programming language, you can use the switch statement. Like normal program execution, a switch statement is evaluated from top to bottom.

Instead of having a long list of if statements, a switch statement provides much cleaner code.

Switch example

The program below demonstrates the use of a switch statement. The switch statement exists in some other languages like C.

package main

import (
    "fmt"
)

func main() {
        x := 3

        switch x {
            case 0:
                fmt.Println("zero")
            case 1:
                fmt.Println("one")
            case 2:
                fmt.Println("two")             
            case 3:
                fmt.Println("tres")
        }
}

This outputs 'tres' because x is equal to 3. Instead of having a bulk of if statements you can use this.

The above program may not make sense, because we use a predefined condition. What if you you get it with keyboard input?

But instead of normal keyboard input, you need integer input. You can scan an integer like this:

fmt.Print("Enter x: ")
in := bufio.NewScanner(os.Stdin)
in.Scan()
x,_ := strconv.Atoi(in.Text())

So the switch statement with keyboard input gives:

package main

import (
    "fmt"
    "bufio"
    "os"
    "strconv"
)

func main() {
        fmt.Print("Enter x: ")
        in := bufio.NewScanner(os.Stdin)
        in.Scan()
        x,_ := strconv.Atoi(in.Text())

        switch x {
            case 0:
                fmt.Println("zero")
            case 1:
                fmt.Println("one")
            case 2:
                fmt.Println("two")             
            case 3:
                fmt.Println("tres")
        }
}