无法在标题中引用枚举 [英] Cannot refer to enum in header

问题描述

你好，

我试图自学C ++并且对头文件不太了解。当我尝试按如下方式创建一个时，我得到了一个我不明白的奇怪错误。我试过谷歌搜索，但我对C ++编译/链接过程缺乏了解是一个障碍。





无论如何，这里是头文件（删除了不必要的代码）



GraphicsLib.h

Hello,
I trying to self-learn C++ and don't have much idea about header files. When I tried to create one as follows, I got a strange error that I do not understand. I have tried googling but my lack of understanding about C++ compiling/linking process is an obstacle.


Anyway, here is the header file (unnecessary code removed)

GraphicsLib.h

#ifndef GRAPHICS_LIB_INCLUDE
#define GRAPHICS_LIB_INCLUDE

enum BorderTypes
{
SINGLE_ALL,
DOUBLE_ALL,
SINGLE_SIDE_DOUBLE_TOP,
DOUBLE_SIDE_SINGLE_TOP
};

static void DrawMessageWithBox(std::string message, BorderTypes borderType, int length);
#endif // GRAPHICS_LIB_INCLUDE

GraphicsLib.cpp文件

The GraphicsLib.cpp file

include "GraphicsLib.h"

static void DrawMessageWithBox(string message, BorderTypes borderType, int length)
{
    //Draw the box and the message

}

主程序

The main program

#include<iostream>
#include "GraphicsLib.h"
using namespace std;

int main()
{
   DrawMessageWithBox("HELLO WORLD", BorderTypes.DOUBLE_ALL, 77);

   return 0;
}

每当我尝试编译程序时，都会收到此错误 -



[错误]'''之前的预期主要表达式''令牌



如果我更换功能用这个调用，

Whenever I try to compile the program, I get this error -

"[ERROR] Expected primary-expression before '.' token"

If I replace the function call with this one,

DrawMessageWithBox("HELLO WORLD", DOUBLE_ALL, 77);

我得到以下错误 -

[警告]'void DrawCenteredMessageWithBox（std :: string，BorderTypes，int）'已使用但从未定义[默认启用]

在函数'main'中：

未定义引用`DrawCenteredMessageWithBox（std :: string，BorderTypes，int）'





有谁能告诉我我做错了什么？

谢谢。

I get the following error -
"[Warning] 'void DrawCenteredMessageWithBox(std::string, BorderTypes, int)' used but never defined [enabled by default]"
In function 'main':
"undefined reference to `DrawCenteredMessageWithBox(std::string, BorderTypes, int)' "


Can anyone please tell me what am I doing wrong?
Thanks.

推荐答案

In第一种情况，你不需要 BorderTypes。前缀你的枚举值。在第二种情况下，您可以在某处（未显示）调用 DrawCenteredMessageWithBox ，但该函数从未被定义过。



[edit]

参见Jochen的解决方案条目。

[/ edit]

In the first case you do not need the BorderTypes. prefix on your enum values. In the second case you have a call to DrawCenteredMessageWithBox somewhere (not shown), but that function has never been defined.

[edit]
See also Jochen's Solution entry.
[/edit]

使用枚举你必须使用两个冒号名称与枚举者之间：

With enums you must use two colons between the name and the enumerator:

DrawMessageWithBox("HELLO WORLD", BorderTypes::DOUBLE_ALL, 77);

Quote：

[Warning]'void DrawCenteredMessageWithBox（std :: string，BorderTypes，int）'已使用但从未定义[已启用]默认情况下]

函数'main'：

未定义引用`DrawCenteredMessageWithBox（std :: string，BorderTypes，int）'

"[Warning] 'void DrawCenteredMessageWithBox(std::string, BorderTypes, int)' used but never defined [enabled by default]"
In function 'main':
"undefined reference to `DrawCenteredMessageWithBox(std::string, BorderTypes, int)' "

您无法访问源文件外的 static 函数。删除 static 限定符以获取对它的访问权限。

You cannot access static functions outside their source file. Remove the static qualifier in order to gain access to it.

这篇关于无法在标题中引用枚举的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！