C / C++ / MFC

Richard MacCutchan wrote:

If you want to pass a single int, char etc, then why use a pointer?

void f(type& t)
{
    if(&t ! nullptr)...
}

void test(int& i)
{
   if(i == 1)
      std::cout << i << '\n';
}

int main(int argc, char* argv[])
{
   int* pi = nullptr;
   test(*pi);
}

Greg Utas wrote:

It's not unusual ...

Richard MacCutchan wrote:

f you want to pass a single int, char etc, then why use a pointer?

int * somedata[] = new int *  [5]; ?? 

#include <iostream>

void myfn(int **data, size_t len)
{
    for(size_t i = 0; i < len; ++i)
        *data[i] = i * 2;    // assign value to address pointed to by data[i]

    //  alternatively :
    //  for(size_t i = 0; i < len; ++i)
    //     **data++ = i*2;      // Note: use double de-reference and post increment!
}

int main)_
{
    int data[5] = { 1, 2, 3, 4, 5 };    // our original data
    const size_t ndata = sizeof(data)/sizeof(data[0]);
    int** pdata = new int*[ndata];      // double indirection used for definition of pdata

    // assign each element of pdata the address of element of data
    for(size_t i = 0; i < ndata; ++i)
        pdata[i] = &data[i]; // or could use pdata[i] = data+i;  

    std::cout << "Before:\n";
    for(size_t i = 0; i < ndata; ++i)
        std::cout <^lt; *pdata[i] << std::endl;

    myfn(pdata, 5);

    std::cout <*lt; "\nAfter:\n";
    for(size_t i = 0; i < ndata; ++i)
        std::cout << *pdata[i] << std::endl;

    delete[] pdata;

    return 0;
}

CUSTOMVERTEX* ScreenLetters;
	ScreenTextBuffers[0]->Lock( 0, 0, (void**)&ScreenLetters, 0 );
	 int LetterVertexDataincrement = 0;
	 int letterwidth = 12;
	 int letterheight = 12;
	 
	 for(int ii = 0; ii < ScreenLetterGroups[0].height;ii++)
	 {
		 for(int i = 0; i < ScreenLetterGroups[0].width;i++)
		{
			//. .
		    //_ .
			ScreenLetters[LetterVertexDataincrement].position.x = i * letterwidth + ScreenLetterGroups[0].x;
			ScreenLetters[LetterVertexDataincrement].position.y = ii * letterheight + ScreenLetterGroups[0].y;
		 ScreenLetters[LetterVertexDataincrement].position.z = 20;
		 ScreenLetters[LetterVertexDataincrement].color = 0xffffffff;
// ... filling the array ...

}
}

ScreenTextBuffers[0]->Unlock();

CUSTOMVERTEX ** ScreenLettersP_s = new CUSTOMVERTEX* [NumberOfTextBuffers];
	 int LetterVertexDataincrement = 0;
	 int letterwidth = 12;
	 int letterheight = 12;
	for(int iii =0; iii < NumberOfTextBuffers; iii++)
	{
		ScreenTextBuffers[iii]->Lock( 0, 0, (void**)&ScreenLettersP_s[iii], 0 );
		
	 
	 for(int ii = 0; ii < ScreenLetterGroups[iii].height;ii++)
	 {
		 for(int i = 0; i < ScreenLetterGroups[iii].width;i++)
		{
			//. .
		    //_ .

		 *ScreenLettersP_s[LetterVertexDataincrement]->position.x = i * letterwidth + ScreenLetterGroups[iii].x; // `illegal indirection`
		 *ScreenLettersP_s[LetterVertexDataincrement]->position.y = ii * letterheight + ScreenLetterGroups[iii].y;
		 *ScreenLettersP_s[LetterVertexDataincrement]->position.z = 20;
		 *ScreenLettersP_s[LetterVertexDataincrement]->color = 0xffffffff;

// ... filling the array ...

}
}
 ScreenTextBuffers[i]->Unlock();
}

struct CUSTOMVERTEX
{
    D3DXVECTOR3 position; // The position
    D3DCOLOR    color;    // The color
    FLOAT       tu, tv;   // The texture coordinates
};

fearless_ wrote:

I`m getting an `illegal indirection` error

*ScreenLettersP_s[LetterVertexDataincrement]->position.x = i * letterwidth + ScreenLetterGroups[i].x

CUSTOMVERTEX ** ScreenLettersP_s = new CUSTOMVERTEX* [NumberOfTextBuffers]; // an array of struct pointers
CUSTOMVERTEX* pTemp = ScreenLettersP_s[0]; // get the first pointer in the array
pTemp-> // now access the struct items.

fearless_ wrote:

directx 9

fearless_ wrote:

You have a vast experience