输入小于9时如何停止Go循环？

Question

var (
        value1, value2 float64
    )
for value1 < 9 || value2 < 9 || value1 < 9 && value2 < 9 {
    fmt.Print("Masukan berat belanjaan di dalam kantong : ")
    fmt.Scan(&value1, &value2)
}

fmt.Println("Program Selesai")

I want the program does looping to show inputs from the user and stop when one of the two inputs is less than 9. But the program always stops when both of value is more than or equals 9. Help me to fix it.

Answer 1

I recommend using a function:

func input(value *float64) bool {
    fmt.Print("Enter the weight of the grocery in the bag (less than 9 ends the loop):")
    _, err := fmt.Scan(value)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("You entered:", *value)
    return *value >= 9.0
}

Which makes your main loop very clean:

    for input(&value1) && input(&value2) {
    }

You may try this:

package main

import (
    "fmt"
    "log"
)

func main() {
    value1, value2 := 0.0, 0.0
    for input(&value1) && input(&value2) {
    }
    fmt.Println("Done.")
}

func input(value *float64) bool {
    fmt.Print("Enter the weight of the grocery in the bag (less than 9 ends the loop):")
    _, err := fmt.Scan(value)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("You entered:", *value)
    return *value >= 9.0
}

Output:

Enter the weight of the grocery in the bag (less than 9 ends the loop):12
You entered: 12
Enter the weight of the grocery in the bag (less than 9 ends the loop):7
You entered: 7
Done.

---

You may initialize values to a number like 9.0 or greater, so you don't need to use the break:

    value1, value2 := 9.0, 9.0
    for value1 >= 9 && value2 >= 9 {
        fmt.Print("Masukan berat belanjaan di dalam kantong : ")
        fmt.Scan(&value1, &value2)
    }

And check for errors, e.g.:

        if _, err := fmt.Scan(&value1, &value2); err != nil {
            panic(err)
        }