告诉我这段代码GOLANG有什么问题 [英] Tell me what's wrong with this code GOLANG

问题描述

package main

import (
    "fmt"
    "math"
)

func main() {

    distencecalc()
}

func distencecalc() {

    fmt.Println("X1 :")
    var x1 float64
    fmt.Scanf("%f", &x1)
    fmt.Print("")
    fmt.Println("Y1 :")
    var y1 float64
    fmt.Scanf("%f", &y1)
    fmt.Print("")
    fmt.Println("Z1 :")
    var z1 float64
    fmt.Scanf("%f", &z1)
    fmt.Print("")
    fmt.Println("X2 :")
    var x2 float64
    fmt.Scanf("%f", &x2)
    fmt.Print("")
    fmt.Println("Y2 :")
    var y2 float64
    fmt.Scanf("%f", &y2)
    fmt.Print("")

    fmt.Println("Z2 :")
    var z2 float64
    fmt.Scanf("%f", &z2)
    fmt.Print("")

    var Xcalc = x2 - x1
    var Ycalc = y2 - y1
    var Zcalc = z2 - z1



    var calcX = math.Pow(Xcalc, 2)
    var calcY = math.Pow(Ycalc, 2)
    var calcZ = math.Pow(Zcalc, 2)


    var allcalc = calcX + calcZ + calcY
    fmt.Println("the result is :")
    fmt.Println(math.Sqrt(allcalc))
}

问题是我先编译然后运行它询问x1的程序，然后输入值，同时询问y1和z1.

The problem is I compile then run the program it asks about x1 I enter the value and it asks about y1 and z1 at the same time.

推荐答案

实际上，所讨论的代码可在Unix系统上运行，但通常出现的问题是像 fmt.Scanf(％f"，& x1)不使用换行符，而是引用 fmt的软件包文档中的引用:扫描 :

Actually the code in question works on unix systems, but usually the problem is that calls like fmt.Scanf("%f", &x1) does not consume newlines, but quoting from package doc of fmt: Scanning:

扫描，Fscan，Sscan将输入中的换行符视为空格.

Scan, Fscan, Sscan treat newlines in the input as spaces.

在Windows上，换行符不是单个 \ n 字符，而是 \ r \ n ，因此后续的 fmt.Scanf()呼叫将立即进行，而无需等待用户的进一步输入.

And on Windows the newline is not a single \n character but \r\n, so the subsequent fmt.Scanf() call will proceed immediately without waiting for further input from the user.

因此，您必须在格式字符串中添加换行符，以避免随后的 fmt.Scanf()调用继续进行:

So you have to add a newline to your format string to avoid subsequent fmt.Scanf() call to proceed:

fmt.Scanf("%f\n", &x1)

但是更容易的是只使用 fmt.Scanln() 并跳过整个格式字符串:

But easier would be to just use fmt.Scanln() and skip the whole format string:

fmt.Scanln(&x1)

Scanln，Fscanln和Sscanln停止在换行符处进行扫描，并要求在这些项目之后加上换行符或EOF.

Scanln, Fscanln and Sscanln stop scanning at a newline and require that the items be followed by a newline or EOF.

扫描仪函数( fmt.ScanXXX())返回成功扫描的项目数和错误.要确定扫描是否成功，您必须检查其返回值，例如:

The scanner functions (fmt.ScanXXX()) return you the number of successfully scanned items and an error. To tell if scanning succeeded, you have to check its return value, e.g.:

if _, err := fmt.Scanln(&x1); err != nil {
    fmt.Println("Scanning failed:", err)
}

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