我正在制作一个可扩展的Arduino库，但收到编译器错误：invalid use of non-static data member。
我的代码： LedCube.h：
#ifndef LedCube_h
#define LedCube_h
#include "Arduino.h"
class LedCube {
private:
int _x, _y, _z;
byte _lPins[_y];
byte _cPins[_z][_x];
public:
LedCube(int x, int y, int z, byte *lPins, byte (*cPins)[_x]);
void displayFrame(bool frame[][_x][_z]);
void displayLayer(int i, bool frame[][_x][_z]);
};
#endif
Ledcube.ino（CPP）：
#include "Arduino.h"
#include "LedCube.h"
int _x, _y, _z;
//bool frame[y][z][x] = {0};
byte _lPins[_y];
byte _cPins[_z][_x];
LedCube::LedCube(int x, int y, int z, byte lPins[], byte cPins[][_x]) {
_x = x;
_y = y;
_z = z;
_lPins = lPins;
_cPins = cPins;
}
void LedCube::displayFrame(bool frame[_y][_x][_z]) {
int i;
for(i=0;i<_y;i++) {
displayLayer(i, frame);
pinMode(_lPins[i], OUTPUT);
delay(1);
pinMode(_lPins[i], INPUT);
}
}
void LedCube::displayLayer(int i, bool frame[_y][_x][_z]) {
int j,k;
for(j=0;j<_z;j++) {
for(k=0;k<_x;k++) {
if(frame[i][j][k]) {
digitalWrite(_cPins[j][k], HIGH);
}
else {
digitalWrite(_cPins[j][k], LOW);
}
}
}
}
我想接受变量x，y和z，并在构造函数中将它们设置为_x，_y和_z ，因此不想设置变量static。
我正在使用这些变量来声明循环。
我得到的错误是：
Arduino: 1.6.5 (Windows 10), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
int _x, _y, _z;
^
LedCube.h:13: error: from this location
byte _lPins[_y];
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
int _x, _y, _z;
^
LedCube.h:14: error: from this location
byte _cPins[_z][_x];
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube.h:14: error: from this location
byte _cPins[_z][_x];
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube.h:16: error: from this location
LedCube(int x, int y, int z, byte *lPins, byte (*cPins)[_x]);
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube.h:17: error: from this location
void displayFrame(bool frame[][_x][_z]);
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
int _x, _y, _z;
^
LedCube.h:17: error: from this location
void displayFrame(bool frame[][_x][_z]);
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube.h:18: error: from this location
void displayLayer(int i, bool frame[][_x][_z]);
^
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
int _x, _y, _z;
^
LedCube.h:18: error: from this location
void displayLayer(int i, bool frame[][_x][_z]);
^
LedCube:6: error: array bound is not an integer constant before ']' token
LedCube:7: error: array bound is not an integer constant before ']' token
LedCube:7: error: array bound is not an integer constant before ']' token
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube:9: error: from this location
LedCube.ino: In constructor 'LedCube::LedCube(...)':
LedCube:10: error: 'x' was not declared in this scope
LedCube:11: error: 'y' was not declared in this scope
LedCube:12: error: 'z' was not declared in this scope
LedCube:13: error: '_lPins' was not declared in this scope
LedCube:13: error: 'lPins' was not declared in this scope
LedCube:14: error: '_cPins' was not declared in this scope
LedCube:14: error: 'cPins' was not declared in this scope
In file included from LedCube.ino:2:0:
LedCube.h: At global scope:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
int _x, _y, _z;
^
LedCube:17: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube:17: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
int _x, _y, _z;
^
LedCube:17: error: from this location
LedCube.ino: In member function 'void LedCube::displayFrame(...)':
LedCube:20: error: 'frame' was not declared in this scope
LedCube:21: error: '_lPins' was not declared in this scope
In file included from LedCube.ino:2:0:
LedCube.h: At global scope:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_y'
int _x, _y, _z;
^
LedCube:27: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_x'
int _x, _y, _z;
^
LedCube:27: error: from this location
In file included from LedCube.ino:2:0:
LedCube.h:12: error: invalid use of non-static data member 'LedCube::_z'
int _x, _y, _z;
^
LedCube:27: error: from this location
LedCube.ino: In member function 'void LedCube::displayLayer(...)':
LedCube:31: error: 'frame' was not declared in this scope
LedCube:31: error: 'i' was not declared in this scope
LedCube:32: error: '_cPins' was not declared in this scope
LedCube:35: error: '_cPins' was not declared in this scope
invalid use of non-static data member 'LedCube::_y'
This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.
我只想针对此错误而不是输出中的其他错误。
答案 0 :(得分：3)
class LedCube {
private:
int _x, _y, _z;
byte _lPins[_y];
byte _cPins[_z][_x];
以上代码没有任何意义，Arduino与否。 （请记住Arduino使用C ++）。
您正在尝试定义长度为_lPins且未初始化的数组_cPins和_x, _y, _z。类必须具有固定的大小，以便在实例化时，编译器知道分配它的内存量（在调用构造函数之前）。如何为未知大小的数组分配内存？
（已编辑添加）
我认为StackOverflow有一个建设性的答案政策。如果你认为我做错了，请给出一个解决方案（这就是我在这里的原因）。
我很有兴趣知道为什么你会接受一个答案，说明＆＃34;你的代码：......是错的。＆＃34;但我的冒犯。接受的答案没有发布解决方案代码，只是一些指导原则。
你的这段代码，不在类定义中，也会犯同样的错误：
int _x, _y, _z;
//bool frame[y][z][x] = {0};
byte _lPins[_y];
byte _cPins[_z][_x];
这也会产生错误。您不能声明这样的静态数组，其边界为x, _y, _z，其中x, _y, _z不是常量。当您更改x, _y, _z时，阵列将来不会重新定义其长度。
在构造函数中，您将作为参数传递，名称_x也是类变量。
LedCube::LedCube(int x, int y, int z, byte lPins[], byte cPins[][_x]) {
C ++不允许您分配这样的数组：
_lPins = lPins;
_cPins = cPins;
你有很多错误，而不仅仅是一个，例如
LedCube:20: error: 'frame' was not declared in this scope
LedCube:21: error: '_lPins' was not declared in this scope
你真的应该经历并清理它们。
同样，您的平台上也未提供IIRC，new和delete
实际上，Arduino提供new和delete，以及malloc和free。
我试图建设性，但没有一线修复。需要返工，很遗憾地告诉你。你可能想做一些C ++教程。您正在编写的代码（虽然我可以看到您要执行的操作）是希望该语言以某种方式工作，当它只是没有。
下面是根据提供的数组大小在构造函数中分配引脚结构的可能方法。我不认为这是一个很好的实现，但至少它是有效的。 showPins函数显示数据已正确保留。
class LedCube {
private:
const int x_, y_, z_;
byte * lPins_;
byte * cPins_;
public:
LedCube(const int x, const int y, const int z, byte *lPins, byte *cPins); // constructor
void showPins () const;
};
byte lPins [3] = { 5, 6, 7 };
byte cPins [2] [4] = {
{ 1, 2, 3, 4 }, // 0
{ 8, 9, 10, 11 }, // 1
};
LedCube::LedCube (const int x, const int y, const int z, byte *lPins, byte *cPins)
: x_ (x), y_ (y), z_ (z)
{
lPins_ = new byte [y];
cPins_ = new byte [x * z];
if (lPins_ == NULL || cPins_ == NULL)
exit (1);
memcpy (lPins_, lPins, sizeof (byte) * y);
memcpy (cPins_, cPins, sizeof (byte) * x * z);
}
void LedCube::showPins () const
{
Serial.println (F("lPins:"));
for (int i = 0; i < y_; i++)
Serial.println (lPins_ [i]);
Serial.println (F("cPins:"));
for (int j = 0; j < x_; j++)
{
Serial.print (F("z = "));
Serial.println (j);
for (int k = 0; k < z_; k++)
Serial.println (cPins_ [j * z_ + k]);
}
}
LedCube foo (2, 3, 4, (byte *) lPins, (byte *) cPins);
void setup()
{
Serial.begin (115200);
Serial.println ();
foo.showPins ();
}
void loop()
{
}
输出：
lPins:
5
6
7
cPins:
z = 0
1
2
3
4
z = 1
8
9
10
11
答案 1 :(得分：2)
您的代码：byte _lPins[_y]; byte _cPins[_z][_x];错了。 C ++不支持可变长度数组，这意味着_y，_x，_z必须是常量表达式。
请记住，对象的大小在编译时必须是常量，并且您不会再次出现该错误。
＆＃34;正确＆＃34;解决此问题的方法是使用std::vector，但我相信它在您的平台上不存在，但您应该检查。 IIRC，唯一可用的库是来自avr-libc的标准C的子集。
您必须自己动态分配内存。同样，IIRC，new和delete也未在您的平台上提供（但同样，您必须检查我），因此您必须使用{{ 1}}和malloc并以旧C方式做事。有关于如何在线进行此操作的大量资源。