invalid subscript error

Iam getting error while compiling the following code.... I know the mistake i have done is a silly one, but could not find it after repeated parsing.. Please help;

Code:

---

short CAppWnd::ProcessData(short *pbuff, unsigned int nParseCount)
{
  unsigned short naaLeadBuffer[12][nParseCount];
  unsigned int nBuffCount = nParseCount / 500;
  unsigned int nPos = 0;

  for(unsigned int nLeadCount = 0; nLeadCount < 12; nLeadCount++)
  {
    for(unsigned int nCount = 0; nCount <= nBuffCount; nCount
      += 500)
    {
      for(unsigned int nSampleCount = 0; nSampleCount < 500; nSampleCount
        += 10)
      {
        naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 2] + *pbuff[nLeadCount][nSampleCount + 3]) / 2;
        naaLeadBuffer[nLeadCount][nPos++]
          = *pbuff[nLeadCount][nSampleCount + 5];
        naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 7] + *pbuff[nLeadCount][nSampleCount + 8]) / 2;
        naaLeadBuffer[nLeadCount][nPos++] = *pbuff[nLeadCount][nSampleCount
          + 10];
      }
    }
  }
return nParsecount;
}

---

error log ==>
./AppWnd.cpp: In member function 'short int CAppWnd::ProcessData(short int*, unsigned int)':
../AppWnd.cpp:491:14: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:491:53: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:493:48: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:495:14: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:495:53: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:497:15: error: invalid types 'short int[unsigned int]' for array subscript
mingw32-make: *** [AppWnd.o] Error 1

You cannot create the array naaLeadBuffer with the size nParseCount. The size in the [] brackets has to be known at compile time.
Try using the new operator instead and allocating the memory dynamically.

Quote:

---

Originally Posted by threahdead

You cannot create the array naaLeadBuffer with the size nParseCount. The size in the [] brackets has to be known at compile time.
Try using the new operator instead and allocating the memory dynamically.

---

Thanks for the reply....
Request you to give a small code snippet !!! Dynamic allocation has always been a problem area for me...

Quote:

---

Originally Posted by MrDanny

Thanks for the reply....
Request you to give a small code snippet !!! Dynamic allocation has always been a problem area for me...

---

@threahdead can you please help me....

You will need an array of 12 x nParseCount, which basically is a

Code:

---

const int bufferSize = 12;
unsigned short **naaLeadBuffer;
naaLeadBuffer = new unsigned short *[bufferSize];
for(int i = 0; i < bufferSize; i++){
    naaLeadBuffer[i] = new unsigned short[nParseCount];
}

---

naaLeadBuffer will have space for 12 pointers to an unsigned short. Every pointer must point to valid data, which is ensured in the for loop. The data it points to is nParseCount shorts long.

Quote:

---

Originally Posted by threahdead

You will need an array of 12 x nParseCount, which basically is a

Code:

---

const int bufferSize = 12;
unsigned short **naaLeadBuffer;
naaLeadBuffer = new unsigned short *[bufferSize];
for(int i = 0; i < bufferSize; i++){
    naaLeadBuffer[i] = new unsigned short[nParseCount];
}

---

naaLeadBuffer will have space for 12 pointers to an unsigned short. Every pointer must point to valid data, which is ensured in the for loop. The data it points to is nParseCount shorts long.

---

Am getting the same error !!!

../AppWnd.cpp:497:14: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:497:53: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:499:48: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:501:14: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:501:53: error: invalid types 'short int[unsigned int]' for array subscript
../AppWnd.cpp:503:15: error: invalid types 'short int[unsigned int]' for array subscript
mingw32-make: *** [AppWnd.o] Error 1

the 499:48 points to
naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
+ 2] + *pbuff[nLeadCount][nSampleCount + 3]) / 2;

The problems aren't actually to do with memory allocation in this case. Look at the lines like this in the loop body

Code:

---

      naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 2] + *pbuff[nLeadCount][nSampleCount + 3]) / 2;

---

Note the two bits I've highlighted in red and orange. Each of those is triple-dereferencing pbuff (for example, acting as if it is a two-dimensional array of pointers). However, pbuff is just a humble pointer to short, and cannot be triple-dereferenced.

Quote:

---

Originally Posted by grumpy

The problems aren't actually to do with memory allocation in this case. Look at the lines like this in the loop body

Code:

---

      naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 2] + *pbuff[nLeadCount][nSampleCount + 3]) / 2;

---

Note the two bits I've highlighted in red and orange. Each of those is triple-dereferencing pbuff (for example, acting as if it is a two-dimensional array of pointers). However, pbuff is just a humble pointer to short, and cannot be triple-dereferenced.

---

pbuff actually is a pointer to a 2d short buffer...

Code:

---

short naaParseBuffer[12][buffsize];
{
----
-------
------

naaParseBuffer[10][nParseCount] = naFiltered[6];
naaParseBuffer[11][nParseCount] = naFiltered[7];

--------
-----
}

ProcessData(&naaParseBuffer[0][0],
                  nParseCount);

---

Code:

---

short CAppWnd::ProcessData(short *pbuff, unsigned int nParseCount)
{
  unsigned short naaLeadBuffer[12][nParseCount];
  unsigned int nBuffCount = nParseCount / 500;
  unsigned int nPos = 0;

  for(unsigned int nLeadCount = 0; nLeadCount < 12; nLeadCount++)
  {
    for(unsigned int nCount = 0; nCount <= nBuffCount; nCount
      += 500)
    {
      for(unsigned int nSampleCount = 0; nSampleCount < 500; nSampleCount
        += 10)
      {
        naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 2] + *pbuff[nLeadCount][nSampleCount + 3]) / 2;
        naaLeadBuffer[nLeadCount][nPos++]
          = *pbuff[nLeadCount][nSampleCount + 5];
        naaLeadBuffer[nLeadCount][nPos++] = (*pbuff[nLeadCount][nSampleCount
          + 7] + *pbuff[nLeadCount][nSampleCount + 8]) / 2;
        naaLeadBuffer[nLeadCount][nPos++] = *pbuff[nLeadCount][nSampleCount
          + 10];
      }
    }
  }
return nParsecount;
}

---

Quote:

---

Originally Posted by MrDanny

pbuff actually is a pointer to a 2d short buffer...

---

That is consistent with my description of pbuff as a pointer to short. However, the way you are using pbuff in the loop is inconsistent with that, hence the compiler diagnostics.

Quote:

---

Originally Posted by threahdead

You will need an array of 12 x nParseCount, which basically is a

Code:

---

const int bufferSize = 12;
unsigned short **naaLeadBuffer;
naaLeadBuffer = new unsigned short *[bufferSize];
for(int i = 0; i < bufferSize; i++){
    naaLeadBuffer[i] = new unsigned short[nParseCount];
}

---

naaLeadBuffer will have space for 12 pointers to an unsigned short. Every pointer must point to valid data, which is ensured in the for loop. The data it points to is nParseCount shorts long.

---

Suggest you use std::vector instead of error-prone manual memory allocation which you have to free later.
std::vector<std::vector<T>> vec(inner_dim, std::vector(outer_dim));