c++ - 使用指向 "return"多维数组的函数指针

Question

我想将字符数组 micPointsChar[] 传递给函数 initMicPoints() 并将其解析为多维数组 micPoints。我能够使用一维数组成功地做到这一点:

char micPointsChar[30 + 1] = {};
float *initMicPoints(char micPointsChar[], float micPoints[3]);

int main()
{
  // Read in mic points from file
    char micPointsChar[40] = "2,3.343,4.432\n";
    float micPoints[3] = {};
    float *newMicPoints = initMicPoints(micPointsChar, micPoints);
    for (int i = 1; i <= 3; i++)
    {
      Serial.print(newMicPoints[i]);
      Serial.print("\n");
    }
    return 0;
}


float *initMicPoints(char micPointsChar[], float micPoints[3])
{
  static int i = 1;
  static int micNum = 1;
  static int numMics = 1;
  float coordinateDec = 0;

  char *coordinate = strtok(micPointsChar, ",\n");
  coordinateDec = atof(coordinate);
  while (micNum <= numMics)
  {
    while (i <= ((micNum * 3)) && (coordinate != NULL))
    {
      if (i == ((micNum * 3) - 2))
      {
        micPoints[1] = coordinateDec;
      }
      else if (i == ((micNum * 3) - 1))
      {
        micPoints[2] = coordinateDec;
      }
      else if (i == ((micNum * 3) - 0))
      {
        micPoints[3] = coordinateDec;
      }
      coordinate = strtok(NULL, ",\n");
      coordinateDec = atof(coordinate);
      i++;
    }
    micNum++;
  }
  return micPoints;
}

这输出预期的:

2.00
3.34
4.43

但是，当我更改代码以处理多维数组时，micPoints[360][3]:

char micPointsChar[30 + 1] = {};
float *initMicPoints(char micPointsChar[], float micPoints[360][3]);

int main()
{
  // Read in mic points from file
    char micPointsChar[40] = "2,3.343,4.432\n";
    float micPoints[360][3] = {};
    float *newMicPoints = initMicPoints(micPointsChar, micPoints);
    static int i = 0;
    for (i = 1; i <= 3; i++)
    {
      Serial.print(*newMicPoints[i][0]);
      Serial.print("\n");
      Serial.print(*newMicPoints[i][1]);
      Serial.print("\n");
      Serial.print(*newMicPoints[i][2]);
      Serial.print("\n");
    }
    return 0;
}


float *initMicPoints(char micPointsChar[], float micPoints[360][3])
{
  static int i = 1;
  static int micNum = 1;
  static int numMics = 1;
  float coordinateDec = 0;

  char *coordinate = strtok(micPointsChar, ",\n");
  coordinateDec = atof(coordinate);
  while (micNum <= numMics)
  {
    while (i <= ((micNum * 3)) && (coordinate != NULL))
    {
      if (i == ((micNum * 3) - 2))
      {
        micPoints[i][0] = coordinateDec;
      }
      else if (i == ((micNum * 3) - 1))
      {
        micPoints[i][1] = coordinateDec;
      }
      else if (i == ((micNum * 3) - 0))
      {
        micPoints[i][2] = coordinateDec;
      }
      coordinate = strtok(NULL, ",\n");
      coordinateDec = atof(coordinate);
      i++;
    }
    micNum++;
  }
  return micPoints;
}

我收到一个编译时错误:

cannot convert 'float (*)[3]' to 'float*' in return

我是不是把它弄得太复杂了？返回多维数组的最佳方法是什么？

Answer 1

首先，不幸的是

float *initMicPoints(char micPointsChar[], float micPoints[360][3])

被视为

float *initMicPoints(char* micPointsChar, float (*micPoints)[3])

您可以通过引用传递以保持大小:

float *initMicPoints(char* micPointsChar, float (&micPoints)[360][3])

然后当你返回 micPoints

返回类型应为 float (&)[360][3] 或 float (&)[360][3]

这给了一个丑陋的

float (&initMicPoints(char* micPointsChar, float (&micPoints)[360][3]))[360][3]

在调用站点:

float (&newMicPoints)[360][3] = initMicPoints(micPointsChar, micPoints);

首选语法更清晰的 std::array 或 std::vector。