why fmt.Scanf("%s", &name) print the previous value-CodePudding

I make this code for learning:-

package main

import (
    "fmt"
    "strconv"
)

func main() {

    for {
        name := ""
        fmt.Print("Enter : ")
        fmt.Scanf("%s", &name)
        b1, _ := strconv.ParseBool(name)
        fmt.Printf("%T, %v\n", b1, b1)
    }

}

output:

Enter : True

bool, true

Enter : bool, false

Enter :

why there is an extra "Enter: bool, false" line? edit: this will happen in Powershell, cmd and bash in windows but not in wsl.

CodePudding user response：

I assume you're using some IDE.

sometimes they mess up the console output, try to run directly from native terminal instead. Or use vscode.

CodePudding user response：

i had retype your code and i got the same as Sombriks, you must have pressed enter key by mistake.

here is a screenshot

package main

import (
    "fmt"
    "strconv"
)

func main() {
    for {

        name := ""
        fmt.Print("Enter: ")
        fmt.Scanf("%s", &name)
        b, _ := strconv.ParseBool(name)
        fmt.Printf("%T -  %v\n", b, b)
    }
}

CodePudding user response：

this issue is only in windows.

Solved by adding the new line in the "%s\n" format strings. As in this answer

the new cross-platform working code :

package main

import (
    "fmt"
    "strconv"
)

func main() {

    for {
        var name string
        fmt.Print("Enter : ")
        fmt.Scanf("%s\n", &name)
        b1, _ := strconv.ParseBool(name)
        fmt.Printf("%T, %v \n", b1, b1)
    }

}