Question

我目前正在开始通过Arduino编程学习C ++。我正在编写一个8 * 8 LED矩阵，目前有一个半工作代码，它使用操纵杆来控制屏幕上的点。唯一的问题是：它的长度接近1000行。这相当于写了一篇长达1000页的文章，一遍又一遍地说“猪，毯子，市场”，直到我了解所涉及的实际逻辑。

我的朋友建议缩短它，我可以创建一个返回一个字节的函数。

如何做到这一点？

#include "LedControl.h"

LedControl lc=LedControl(12,11,10,1);
// Pins: DIN,CLK,CS, # of Display connected

// I put all the points on the matrix into an array.
// Ex. a11 is an array which there is a dot at the point (1,1)
// a23 is an array which holds the point (2,3), etc.
// I don't know how to shorten this with for loops, but I know there is a way.
byte a11[] = {
   0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a12[] = {
   0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a13[] = {
   0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a14[] = {
   0x10,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a15[] = {
   0x08,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a16[] = {
   0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a17[] = {
   0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a18[] = {
   0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a21[] = {
   0x00,0x80,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a22[] = {
   0x00,0x40,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a23[] = {
   0x00,0x20,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a24[] = {
   0x00,0x10,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a25[] = {
   0x00,0x08,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a26[] = {
   0x00,0x04,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a27[] = {
   0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a28[] = {
   0x00,0x01,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte a31[] = {
   0x00,0x00,0x80,0x00,0x00,0x00,0x00,0x00,
};
byte a32[] = {
   0x00,0x00,0x40,0x00,0x00,0x00,0x00,0x00,
};
byte a33[] = {
   0x00,0x00,0x20,0x00,0x00,0x00,0x00,0x00,
};
byte a34[] = {
   0x00,0x00,0x10,0x00,0x00,0x00,0x00,0x00,
};
byte a35[] = {
   0x00,0x00,0x08,0x00,0x00,0x00,0x00,0x00,
};
byte a36[] = {
   0x00,0x00,0x04,0x00,0x00,0x00,0x00,0x00,
};
byte a37[] = {
   0x00,0x00,0x02,0x00,0x00,0x00,0x00,0x00,
};
byte a38[] = {
   0x00,0x00,0x01,0x00,0x00,0x00,0x00,0x00,
};
byte a41[] = {
   0x00,0x00,0x00,0x80,0x00,0x00,0x00,0x00,
};
byte a42[] = {
   0x00,0x00,0x00,0x40,0x00,0x00,0x00,0x00,
};
byte a43[] = {
   0x00,0x00,0x00,0x20,0x00,0x00,0x00,0x00,
};
byte a44[] = {
   0x00,0x00,0x00,0x10,0x00,0x00,0x00,0x00,
};
byte a45[] = {
   0x00,0x00,0x00,0x08,0x00,0x00,0x00,0x00,
};
byte a46[] = {
   0x00,0x00,0x00,0x04,0x00,0x00,0x00,0x00,
};
byte a47[] = {
   0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x00,
};
byte a48[] = {
   0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x00,
};
byte a51[] = {
   0x00,0x00,0x00,0x00,0x80,0x00,0x00,0x00,
};
byte a52[] = {
   0x00,0x00,0x00,0x00,0x40,0x00,0x00,0x00,
};
byte a53[] = {
   0x00,0x00,0x00,0x00,0x20,0x00,0x00,0x00,
};
byte a54[] = {
   0x00,0x00,0x00,0x00,0x10,0x00,0x00,0x00,
};
byte a55[] = {
   0x00,0x00,0x00,0x00,0x08,0x00,0x00,0x00,
};
byte a56[] = {
   0x00,0x00,0x00,0x00,0x04,0x00,0x00,0x00,
};
byte a57[] = {
   0x00,0x00,0x00,0x00,0x02,0x00,0x00,0x00,
};
byte a58[] = {
   0x00,0x00,0x00,0x00,0x01,0x00,0x00,0x00,
};
byte a61[] = {
   0x00,0x00,0x00,0x00,0x00,0x80,0x00,0x00,
};
byte a62[] = {
   0x00,0x00,0x00,0x00,0x00,0x40,0x00,0x00,
};
byte a63[] = {
   0x00,0x00,0x00,0x00,0x00,0x20,0x00,0x00,
};
byte a64[] = {
   0x00,0x00,0x00,0x00,0x00,0x10,0x00,0x00,
};
byte a65[] = {
   0x00,0x00,0x00,0x00,0x00,0x08,0x00,0x00,
};
byte a66[] = {
   0x00,0x00,0x00,0x00,0x00,0x04,0x00,0x00,
};
byte a67[] = {
   0x00,0x00,0x00,0x00,0x00,0x02,0x00,0x00,
};
byte a68[] = {
   0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x00,
};
byte a71[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x00,
};
byte a72[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x00,
};
byte a73[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x20,0x00,
};
byte a74[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x10,0x00,
};
byte a75[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x08,0x00,
};
byte a76[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x04,0x00,
};
byte a77[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x02,0x00,
};
byte a78[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x00,
};
byte a81[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,
};
byte a82[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40,
};
byte a83[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x20,
};
byte a84[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x10,
};
byte a85[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x08,
};
byte a86[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x04,
};
byte a87[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x02,
};
byte a88[] = {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,
};
byte none[] = //array where no points are lit {
   0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
};
byte all[] = //array which all points are lit {
   0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
};
int xPin = A1; //Pins for Joystick and starting int's
int yPin = A0;
int buttonPin = 2;
int xPosition = 0;
int yPosition = 0;
int buttonState = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600); //Begin Serial
  lc.shutdown(0,false);  // Wake up displays
  lc.setIntensity(0,5);  // Set intensity levels
  lc.clearDisplay(0);  // Clear Displays
  sa44(); //Starting point
  pinMode(xPin, INPUT); //Declaring joystick
  pinMode(yPin, INPUT);
  pinMode(buttonPin, INPUT_PULLUP);
}
//  I then made a function to display each corresponsing point on the screen.
// For example, point (1,1) is a11, and the function is sa11.
// Point (2,3) is a23 and the function is sa23, etc.
// Again, I probably should have shortened it with for loops, but I don't know how to use them for multiple bytes.

void sa11() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a11[i]);
  }
}
void sa12() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a12[i]);
  }
}
void sa13() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a13[i]);
  }
}
void sa14() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a14[i]);
  }
}
void sa15() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a15[i]);
  }
}
void sa16() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a16[i]);
  }
}
void sa17() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a17[i]);
  }
}
void sa18() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a18[i]);
  }
}
void sa21() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a21[i]);
  }
}
void sa22() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a22[i]);
  }
}
void sa23() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a23[i]);
  }
}
void sa24() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a24[i]);
  }
}
void sa25() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a25[i]);
  }
}
void sa26() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a26[i]);
  }
}
void sa27() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a27[i]);
  }
}
void sa28() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a28[i]);
  }
}
void sa31() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a31[i]);
  }
}
void sa32() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a32[i]);
  }
}
void sa33() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a33[i]);
  }
}
void sa34() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a34[i]);
  }
}
void sa35() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a35[i]);
  }
}
void sa36() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a36[i]);
  }
}
void sa37() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a37[i]);
  }
}
void sa38() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a38[i]);
  }
}
void sa41() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a41[i]);
  }
}
void sa42() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a42[i]);
  }
}
void sa43() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a43[i]);
  }
}
void sa44() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a44[i]);
  }
}
void sa45() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a45[i]);
  }
}
void sa46() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a46[i]);
  }
}
void sa47() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a47[i]);
  }
}
void sa48() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a48[i]);
  }
}
void sa51() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a51[i]);
  }
}
void sa52() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a52[i]);
  }
}
void sa53() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a53[i]);
  }
}
void sa54() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a54[i]);
  }
}
void sa55() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a55[i]);
  }
}
void sa56() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a56[i]);
  }
}
void sa57() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a57[i]);
  }
}
void sa58() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a58[i]);
  }
}
void sa61() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a61[i]);
  }
}
void sa62() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a62[i]);
  }
}
void sa63() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a63[i]);
  }
}
void sa64() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a64[i]);
  }
}
void sa65() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a65[i]);
  }
}
void sa66() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a66[i]);
  }
}
void sa67() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a67[i]);
  }
}
void sa68() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a68[i]);
  }
}
void sa71() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a71[i]);
  }
}
void sa72() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a72[i]);
  }
}
void sa73() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a73[i]);
  }
}
void sa74() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a74[i]);
  }
}
void sa75() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a75[i]);
  }
}
void sa76() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a76[i]);
  }
}
void sa77() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a77[i]);
  }
}
void sa78() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a78[i]);
  }
}
void sa81() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a81[i]);
  }
}
void sa82() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a82[i]);
  }
}
void sa83() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a83[i]);
  }
}
void sa84() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a84[i]);
  }
}
void sa85() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a85[i]);
  }
}
void sa86() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a86[i]);
  }
}
void sa87() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a87[i]);
  }
}
void sa88() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,a88[i]);
  }
}
void snone() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,none[i]);
  }
}
void sall() {
  for (int i = 0; i < 8; i++) {
    lc.setRow(0,i,all[i]);
  }
}

void loop() {
  // put your main code here, to run repeatedly:
  xPosition = analogRead(xPin); //Read x, y, button values
  yPosition = analogRead(yPin);
  buttonState = digitalRead(buttonPin);
  Serial.print("\nX: "); //Print x, y, and button values to console
  Serial.print(xPosition);
  Serial.print(" \nY: ");
  Serial.print(yPosition);
  Serial.print(" \nButton: ");
  Serial.println(buttonState);
// This is the Logic behind it.
// The values range from 0 to 700: 340-350 being at rest, 0 being down, and 700 being up.
  if(xPosition < 250 && xPosition > 200) {
    sa43();
  }
  if(xPosition > 100 && xPosition < 200) {
    sa42();
  }
  if(xPosition == 0) {
    sa41();
  }
  if(xPosition > 400) {
    sa45();
  }
  if(yPosition == 0 && xPosition > 340 && xPosition < 350) {
    sa54();
  }
  if(yPosition > 600 && xPosition > 340 && xPosition < 350) {
    sa34();
  }
  if(xPosition > 340 && xPosition < 350 && yPosition > 340 && yPosition < 350) {
    sa44();
  }
  delay(10); //Wait 10 milliseconds before scanning for new input
  if(buttonState == 0) {
    //If button is pressed, light up whole screen.
    sall();
  }
}

非常感谢帮助。

Answer 1

此代码的 lot 确实是不必要的。您可以将数组的所有数组和函数重写为1个函数：

void WriteBytes(byte* data, int length)
{
    for (int i = 0; i < length; ++i)
        lc.setRow(0, i, data[i]);
}

然后你会这样称呼它：

byte data[] =
{
   0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00
};
WriteBytes(data, sizeof(data) / sizeof(data[0]));

Answer 2

Jamey D提供了一个很好的答案。 Gernot1976显示了通过动态生成内容来减少数组声明的好方法。

但是，由于您的问题涉及处理实际数组，我可以使用对数组的引用向您展示如何执行此操作。

使用模板，您可以轻松地将数组传递给常用功能。此方法接受对数组的引用。如果您想对大小N进行硬编码，那么您可以完全删除该模板。

template< size_t N >
void WriteBytes( byte (&arr)[N] ){

    for (int i = 0; i < N; ++i){
        lc.setRow(0, i, arr[i]);
    }
}

//Non template:
void WriteBytes( byte (&arr)[8] ){

    for (int i = 0; i < 8; ++i){
        lc.setRow(0, i, arr[i]);
    }
}

但是你的问题要求返回一个数组。所以为了展示方式，这里有一个小例子。因为我没有LedControl＆amp; lc在这些示例中，其行已注释掉。

//Use a typedef to make declarations simpler.
typedef byte (&ArrRef)[8]; //A reference to an array which contains 8 elements (type not variable)

ArrRef func(); //A prototype to prevent the IDE adding one above the typedef.

ArrRef func(){

  static byte arr[8];

  //Dynamically generate contents of array in arr.

  //Return the array
  return arr;
}

//The equivalent to the non-template version, just using a typedef instead.
void WriteBytes( ArrRef arr ); //Prototype.

void WriteBytes( ArrRef arr ){

    for (int i = 0; i < 8; ++i){
        //lc.setRow(0, i, arr[i]);
    }
}

void setup() {

  //Reference the array returned:
  ArrRef ref = func();

  //Use array
  for( byte el : ref ){

    //...
  }

  //Pass to function
  WriteBytes(ref);
}

void loop() {}

我写了更深入的article here，其中介绍了使用指针和数组引用将数组传递给函数的基础知识。

Answer 3

在C ++语言中，数组是指向内存块的指针。因此，您可以返回指向数组的指针。请注意，您不能返回指向函数中创建的数组的指针，因为这个内存可能会被覆盖（也可能会被覆盖）。

byte a[100];
byte b[100];

byte* f(int x)
{
    if(x % 2 == 0)
        return a;
    else
        return b;
}

如何创建一个在C ++中返回字节数组的函数？ Arduino项目

3 个答案: